Multiversal Contagion

by Razalon The Lizardman

Rating: everyone
Tags: Adventure, Princess Celestia, Crossover, Mario, My Little Pony: Friendship is Magic, Alternate Universe, Other, Princess Luna, Thriller
Length: 15765

A viral outbreak has crossed between universes. Dr. Mario doesn't get paid enough for this shiz.

A new tri-colored virus has spread throughout New Donk City, infecting many citizens and forcing the rapid development of a cure: Megavitamins. But not all is as it seems, as the viruses prove to be more intelligent than assumed at first glance. By a stroke of chance, a gateway leading to other worlds now exists in Dr. Mario's workspace, allowing the viruses to escape to Equestria. Now it's up to Dr. Mario to aid Princesses Celestia and Luna to rid their world of this microscopic alien threat before all of Equestria succumbs to their sickly influence.

A Singularverse story

Cover art by Mach-7 on DeviantArt.

Published 2019-07-28 01:40:01 UTC
Last updated 2019-08-18 21:41:53 UTC

Chapter 1

New Donk Times

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Tri-colored virus epidemic infects New Donk City!

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By: Robbie Tallman

An unusual phenomenon had been observed starting two weeks ago in New Donk City of multi-colored snot being blown from people’s noses. What was at first thought to be the work of a strange mushroom was eventually confirmed to be the work of a new virus, the disastrous effects of which were made apparent during last week’s New Donk City Festival, which saw a grand total of 90 people of various races infected and bedridden.

“My heart goes out to all the infected,” Mayor Pauline said when reached for comment. “As mayor, it is my job to see to the well-being of the people of this city. In this particular case, I must put the peoples’ well-being into the hands of professionals, and I have the utmost trust in the doctors of New Donk Clinic.”

The virus, which has been dubbed the Primary Virus due to its specific color scheme consisting of all three primary colors, has proven to spread quickly. According to medical professionals, Primary is actually composed of three individual viruses forming a cohesive unit: Fever, the red one; Chill, the blue one, and Weird, the yellow one, each one having been named for the specific conditions they inflict upon a victim. While Primary spreads fast, we have been assured that a cure is rapidly being developed and the first patients are expected to be administered the new ‘megavitamins’ this weekend.

“First step to diagnosing you, Mr. Widebrim,” Dr. Mario said as he rummaged through the drawers of his work desk, keeping his tone cheery to lift the sickly man’s spirits, “is to see how severe your infection is. Aha!” He pulled out a mushroom with a sickly face; it felt wrinkly underneath his latex gloves.

The taller man sat on the edge of the exam table, red in the face and breathing heavily, his hat and suit laid carefully on the bed next to him. His eyes had a faraway look like he was in a trance and only barely conscious of his surroundings. Attached to his nose was a plastic tube which ran through a machine and into a glass jar. Dr. Mario handed the Sneezeshroom to him and he took it without a word, though, his arm’s movements were slow and tired like it was a struggle to move it.

“Make sure you eat that mushroom very quickly, preferably in one bite,” Dr. Mario explained. “Otherwise, the bad taste will make you spit it out. It will make you sneeze, and I need-a you to help it by blowing through your nose as hard as you can. Can you do that for me?”

Mr. Widebrim nodded without a word.

“Okie Dokie!” Mario set his finger on a switch on the machine. “I’m ready when you’re-a ready!”

Mr. Widebrim popped the Sneezeshroom into his mouth. He made a wretched face as the mushroom’s bitter taste went into effect, but he soldiered on, chewing for a moment before swallowing the whole thing in one gulp. His mouth opened and his eyes closed and he blew a loud, hard sneeze into the plastic tube, filling it with a thick load of multi-colored snot.

Dr. Mario flipped the switch on the machine and it roared to life. Immediately, the snot in the tube was pulled into the machine like a vacuum. Mr. Widebrim did as instructed and repeatedly blew his nose into the tube, expelling as much multi-colored snot as was stuck up his nostrils. The machine expelled the snot into the jar like an ice-cream machine, filling it until it was three-fourths full. The snot was as thick as paint and gradually the three colors shifted until they were neatly stacked atop one another; why exactly that happened was still a mystery.

Mr. Widebrim took a few deep, relaxing breaths once his nose was cleared out.

“That’s a high density of mucus,” Dr. Mario said, observing the jar. “That’s-a gonna need many megavitamins to cure.”

“I’ll take as many as I need,” Mr. Widebrim proclaimed, his voice coming out hard and raspy.

“Good to hear.” Dr. Mario reached into another drawer and pulled out a plastic bottle showing all kinds of medical information about the megavitamins inside, including its total dosage of three hundred milligrams. He handed the bottle to Mr. Widebrim and got to work removing the plastic tube from his nose. “Make sure to take three vitamins every morning and night, one for each color. That should be enough to cure you.”

“Thanks, Dr. Mario,” Mr. Widebrim said as the tube was pulled off of him.

Dr. Mario set the tube down in the sink. Mr. Widebrim put his suit and hat back on and stuffed the megavitamin bottle into a pocket. The two said their goodbyes and Mr. Widebrim stepped out of Dr. Mario’s office.

“Mamma mia,” Dr. Mario said as he shut the door. “I’ll-a never catch a break.” He strode over to the sink and got to work cleaning out the tube. He’d lost count of how many patients he’d had today and still had booked for appointments. It was certainly a boon to his checkbook, that was undeniable, but a growing part of him was wishing he could take a break from his hectic, mucus-filled schedule.

He had just finished cleaning the tube when a strange noise reached his ears in the otherwise silent examination room. He stopped and strained his ears to pinpoint the source of the noise. Was it coming from outside or inside the room? Inside? Yes, inside. It sounded like… tiny voices? Millions of them.

A soft thud sounded behind him and he spun around. His eyes bulged in shock and disbelief at the sight of the mucus-filled jar tipped over, its contents spilling through the opening in the top. The multi-colored mucus was actually lifting itself through the jar. The mucus coalesced into a puddle on the floor, each color neatly separated in its own section, all while Dr. Mario could only stare in stupefied shock and awe.

Then the puddle started crawling across the floor towards the door. Dr. Mario snapped from his shock and instinctively moved to bar the doorway. The puddle stopped in place. Finally, Dr. Mario was able to properly assess the situation. Somehow, this puddle of Primary virus-filled mucus was sapient. That should’ve been impossible, but there was no other explanation for how it managed to get itself out of the jar and move on its own as one cohesive unit. If it was sapient, and it was trying to get outside, then undoubtedly its goal was to infect more people. It suddenly made perfect sense how the virus was able to spread so quickly and easily.

“You’re not-a going anywhere,” he said firmly.

Millions of tiny cries of laughter sounded from the puddle, which made Dr. Mario’s skin crawl and a shiver to travel the length of his spine. Then the puddle retreated across the floor towards the window. Dr. Mario seized the opportunity and rushed over to the drawer containing bottles of megavitamins, pulling one out and unscrewing the lid. The mucus puddle had started scaling the wall under the window by the time he’d reached them. He pulled a couple of yellow pills from the bottle and threw them at the yellow portion of the puddle. The pills hit dead center, producing a sizzling effect upon contact. Tiny screams erupted from the puddle.

Dr. Mario wasted no time, pulling out a larger handful of pills and prepared to drop them onto the puddle, but before he could, the puddle split into two halves and began moving away from each other; one half moved toward the door while the other moved toward the closet on the other side of the room. He focused on the one heading towards the door, tossing pill after pill and doing his best to make sure the appropriate colors hit the corresponding areas of the puddle. The same sizzling effect came with each successful hit. In no time at all, the puddle had disappeared. A brief glance towards the closet showed the other puddle half slipping underneath the door.

Dr. Mario quickly grabbed another bottle from the drawer and sprinted over to the closet door. There was nowhere for the viruses to escape inside, but there was lots of equipment they could potentially infect that he would need thoroughly sanitized should that happen. He threw open the door and raised his hand, full of pills, ready to throw down at the viruses. What he saw stopped him dead in his tracks and his mouth hung agape in stupefied shock once again.

Hovering right in the middle of his supply closet, in the tiny little space that wasn’t occupied by medical equipment and other supplies, was a rectangular section of space carved out; a dimensional doorway that had definitely not been there yesterday. Through it was an infinite expanse of white. Dr. Mario tried and failed to comprehend the sudden existence of this anomaly situated within his workspace. In the bottom of his vision, he saw the viruses piling on top of each other, the mucus puddle flowing through the doorway. The part of him which was determined to kill the viruses was buried under his confusion and incredulity at the sight before him.

The mucus puddle disappeared over the edge of the doorway, snapping Dr. Mario from his shock. He reached a tentative hand out toward the doorway. It passed right through harmlessly and effortlessly as if it was nothing more than air. Emboldened, he lifted a foot and stuck it through, followed by the rest of his body in a second’s time. Satisfied he wouldn’t explode or disintegrate or something equally horrible, he surveyed his surroundings.

Endless white surrounded him on all sides, including beneath him, but his feet touched upon an invisible solid surface. The only thing to break it up were dozens of other-dimensional doorways scattered among the whitescape. He quickly spotted the viruses crawling across the invisible ground of the void and dashed after them. They seemed to be booking it towards the nearest doorway to the one they’d come out of. His heart leapt into his throat when he realized that, if the white void he was in was some kind of dimensional hub world, then there could and probably did exist living, sapient creatures on the other side of each doorway.

The viruses were just in front of the doorway by the time he reached them. He raised his hand up, full of multi-colored megavitamins, and threw them down in a panic, not caring to properly aim to line up the colors. As a result, only a small portion of the puddle was killed. Dr. Mario tsked and reopened the bottle and poured a bunch into the palm of his hand. He began sorting them, glancing every now and then at the puddle to keep track of its movements, his heartbeat increasing with every second. Then he cried out in despair when his fingers slipped, spilling all the megavitamins onto the ground. He knelt down and hurriedly began gathering them again. He looked up and his heart skipped a beat upon seeing the viruses slip over the edge of the dimensional doorway.

He couldn’t waste any time. He ignored the fallen pills and pulled out his second bottle and hurriedly unscrewed the lid. He couldn’t afford to sort through the megavitamins, deciding to just dump the whole bottle onto the viruses. He practically jumped through the doorway, coming out into a dark room with a sliver of light on the ground beneath him. Another supply closet, he guessed. Instinctively, he reached around for a light switch but couldn’t find anything. Then he saw the viruses emerge from the darkness and pass underneath the door.

“What the heck!?” came a gruff, masculine voice from the other side of the door

Dr. Mario ignored the voice. He kicked the door open and scanned the immediate surroundings. The scenery itself escaped his attention as his gaze landed squarely on the viruses crawling across the floor, picking up speed as they scaled the opposite wall under a window. He poured all the bottle’s contents into his hand, rushed forward and reeled back his arm.

“So long-a viruses!”

He threw the pills with all his might. They scattered through the air, heading straight for the viruses. Millions of tiny squeals of terror sounded from the mucus puddle before, to Dr. Mario’s amazement, the bottom half of the puddle lifted up in front of the top half. The megavitamins impacted the impromptu shield, disintegrating it easily and quickly, but ultimately failed to break through to the top half. A million tiny cheers of glee sounded from the puddle before it continued its trek up the wall, making its way onto the windowsill and slipping under the crack to the outside.

Dr. Mario could only watch helplessly as the viruses escaped. He was increasingly impressed by their super intelligence, but more worried about what trouble their existence could spell for the denizens of this world. He would need to retrieve several more megavitamin bottles if he wanted any hope of combating their sky-high transmission rate, but the real challenge would be tracking them down and, potentially, having to cure hundreds or even thousands of victims. He could do it, and he would do it if he had to, but he would definitely need a short vacation afterwards.

Someone cleared their throat behind him and he turned around in surprise, having forgotten someone else had been there. The creatures before him made him stop and do a double-take. They were white, winged horses wearing fancy-looking gold-plated armor. They held spears in the crooks of their hooves and their eyes bore into him with a stern intensity that immediately told him his presence wasn’t exactly welcome. He wasn’t sure what he would’ve expected the denizens of this world to look like, but somehow this felt weird even compared to anything his imagination could’ve cooked up.

He put on his best friendly smile and held up his hands in a placating manner, hoping that would translate to hooved creatures accordingly. “I come in peace,” he said.

The winged horses glanced at each other for a moment in silent communication, nodded, and one of them stepped forward. “We’ll take you to our leader.”

Chapter 2

Dr. Mario’s eyes flitted all around him as the alien equines led him through what must’ve been a castle, judging from the elaborate and exquisite architecture. It wasn’t quite like Princess Peach’s castle which was more welcoming and friendly; this was grand and flaunted high stature. Tall pillars etched with elaborate designs supported the structure, set in between many stained glass windows with more abstract designs. The colors were vibrant— blues, purples, and gold dominated the walls while a plush red carpet lined the floor beneath. He caught a glimpse outside one clear window to behold a wide view of a sprawling cityscape outside the castle, populated with several more colorful equines going about their business.

Everything was so strange and alien, he almost forgot why he was here. Seeing all those strange equines outside brought a sharp, horrifying realization to him. This world was very much populated by sapient creatures. That meant the viruses had plenty of opportunities to spread and cause a new epidemic. How well the sickness translated to alien horses, he didn’t know, but it was a chance he could never take as a professional doctor.

He hurried to fall into step alongside the guards, who turned to look at him curiously. “Heya, fellas, think we can speed this up a bit?” Dr. Mario asked with a worried frown. He tugged at his collar in another gesture he hoped would properly translate. “Your whole kind might be in danger.”

The guards continued looking at him blankly. “But… it’s proper protocol to not run with guests,” one of them said.

Dr. Mario slapped a hand to his face. “Mamma mia.”

They continued on in silence, all the while Dr. Mario fidgeted nervously. They led him up a winding staircase and down a couple more hallways, eventually coming to a stop in front of a set of large double doors. One guard stepped forward and knocked on the door. Dr. Mario almost jumped back when, in response, the door was enveloped in a golden nimbus and cracked open. The other guard gestured for Dr. Mario to enter, which he did after a moment of hesitation, not sure what was going to happen, but the urgency of the situation won out in the end.

He came into a room that was more like a hallway than a room. Along either wall were more stained glass windows, these ones depicting specific events at first glance, but whether they were fiction or not he had no way of knowing. At the other end of the room sat a tall golden throne, upon which sat an equally tall equine with a snow-white coat, a free-flowing multi-colored mane, and dressed head to hoof in golden regalia. What really stuck out were the wings folded at their sides as well as the horn protruding from their head; that was certainly different. Another point of interest was the stylized sun picture on their flank. They had their face buried in a scroll levitating in a golden nimbus just like the door.

“Come forward, my little pony,” came a feminine voice from them.

Dr. Mario began approaching the throne, nervous, but quickly threw caution to the wind and broke out into a jog. The equine lifted her face from the scroll in response, looking afraid for a brief second before her face morphed into surprise. Dr. Mario stopped at the base of the steps leading up to the throne just as she started speaking.

“Oh, goodness, my apologies. Clearly, you are not one of my subjects.” She tilted her head. “You came through the Window, did you not?”

“Your world is in danger, Your Highness!” Dr. Mario blurted, ignoring her. “There’s all these viruses that escaped from my world and came into yours and they cause all these weird symptoms and—”

Dr. Mario stopped when he felt his mouth shut of its own accord as another golden nimbus surrounded it. The royal equine’s horn was surrounded with the same colored nimbus, making it clear where all the strange magic had been coming from. She stepped off her throne and began descending the steps, letting the scroll she was holding fall to the ground.

“I hear your concern, visitor from another world,” she said calmly. “But first I must be sure you are who you say you are, and that your intentions truly are noble.” She stepped onto the floor and closed the distance between them as she continued. “My name is Princess Celestia, diarch of Equestria alongside my sister, Princess Luna. I will allow you to speak, and I want you to, calmly, tell me exactly who you are and why you find yourself in this world. Can you do that?”

Dr. Mario nodded his head. The golden nimbus disappeared from around his mouth and he opened it, inhaling a deep, relaxing breath of air before he exhaled and began speaking. He explained everything she wanted to know: where he came from, his occupation, the Primary Virus outbreak back home, how the samples got loose, the dimensional doorway in his workspace, and how he chased the viruses to this world before they ultimately escaped. Princess Celestia listened attentively, her expression gradually morphing into worry as he went on, but especially as he described the kinds of symptoms the viruses were capable of.

“Yes, that is indeed concerning.” She appeared to stare off into space for a few moments before she asked, “These ‘megavitamins’ you speak of— How many more do you have?”

Dr. Mario silently counted on his fingers before replying, “I have about three dozen bottles, but two-thirds of them are reserved for patients back in my world. I’m-a gonna need to reschedule all of their appointments now…” he trailed off.

Celestia stepped past him and opened the double doors with her magic. “Relay these orders to Guard Captain Microburst: Tell him that, until further notice from the Crown, Canterlot is to be quarantined. No trains are to arrive or depart starting now and all roads are to be cordoned off. An alien virus is roaming free somewhere in the city; we must not let it spread to all of Equestria.”

The guards snapped a salute and rushed down the hallway out of sight. Celestia returned to Dr. Mario with a smile. “My guards work quickly; I have faith this virus won’t slip past us.”

Dr. Mario breathed a sigh of relief. “Sono sollevato.”

“Time is of the essence, so I’ll take us back to that supply closet the quick way.” Her horn lit up again. “This will only disorient you for a second, I promise.”

Before Dr. Mario could ask what she meant, there was a bright flash and the ground fell away under his feet. A second later, the light disappeared. He felt dizzy for a moment and nearly stumbled but righted himself. Looking around, he saw they were now back in the same area where he’d tried to stop the viruses from escaping. The supply closet he’d come out of was right next to them, still open with the dimensional doorway plainly visible.

“Before you go to retrieve more of your megavitamins,” Celestia spoke up, “you need to know how to get back home first.”

Dr. Mario nodded his understanding.

“First things first, that white space you came through is called the Singularity; essentially, it is a hub connecting various worlds that was created a little over a year ago. For the sake of urgency, I won’t go into detail about it until after this crisis is resolved. And those ‘dimensional doorways’ are actually called Windows, as I said before. In order to return to your world, you will need to locate a Guide; look for a set of darkly-colored spheres arranged in a cross pattern. Inform them of your desire to return to your world and make sure to identify the name of your home. Do that, and they’ll summon your world’s Window in an instant.”

“Okie Dokie.” Dr. Mario took off in a sprint through the Window. Coming out into the Singularity, he scanned his surroundings for a being matching the description Celestia gave, quickly finding one hovering in the air above him. “I need to get-a back home to New Donk City, please.”

The Guide lifted a sphere ‘arm’ and a Window a short distance away zipped over to him.

“Grazie!” he shouted before practically diving through. He threw open the supply closet door and rushed into his office. He needed to move and wrap up his loose ends quickly.

He opened the drawer containing his megavitamin bottles and pulled them all out. He set aside a third of them and placed them in a plastic bin. He next exited the room and made his way down the hallway to the receptionist’s desk where the New Donker lady currently on duty looked up from her computer at him as he approached.

“I need-a you to reschedule the rest of my appointments today for tomorrow; some urgent business has come up,” he explained.

The receptionist looked surprised for a moment, but smiled and began typing away at her computer to complete his request.

“Grazie,” he said, and hurried back down the hall.

He was positive he could wrap up this mess before tomorrow. This was certainly not how he expected his day to go, but the thrill of adventure was buzzing within him, and he loved it.

Dr. Mario gathered up his remaining megavitamin bottles and hurried through the Window, quickly making his way back to the world of Equestria. A different set of equine guards were standing watch at the door to the supply closet when he arrived and they instructed him to follow them back to the throne room. On orders from Celestia, they moved at a much brisker pace than the ones before, much to Dr. Mario’s delight.

They brought him to the throne room and bade him enter. Celestia was standing next to the throne, conversing with another winged, horned equine; this one had a similar flowing mane colored blue, a darker blue coat, a stylized moon against a black backdrop on their flank, and was dressed head to hoof in silver regalia. This other equine turned to him once he entered the room, her eyes filled with interest.

“I got the megavitamins, Celestia,” he said, holding out the plastic bin.

“Thank you, Dr. Mario,” she replied, levitating the bin out of his hands. She studied the contents for a moment before saying, “We will need to be conservative with how we spend these.” She passed four bottles each to the three of them.

Dr. Mario flipped one of the bottles in the air in a playful manner. “We can do it,” he said, voice brimming with confidence.

“You carry yourself more as a warrior than a doctor,” the blue equine remarked; her voice was also feminine. She placed a hoof to her chest. “I am Princess Luna, diarch of Equestria alongside my sister. I hope our mission will be successful.”

“I am confident we can solve this crisis before it gets out of hoof,” Celestia said.

“What’s-a the situation, Princesses?” Dr. Mario asked.

“My guards have erected a forcefield around the city from within the castle and the royal nurses are preparing the hospital wing for an influx of sick patients,” Celestia explained. She grimaced. “The descriptions you gave of the effects of this Primary Virus are… disturbing, to say the least.”

“Indeed, but the viruses take a while to take effect,” Dr. Mario said. “We should be able to—”

There was a crash from beside them, followed by a spray of multi-colored glass showering them and causing them to instinctively cover themselves with their arms/wings. A heavy thud sounded a short distance away from them and they turned to see a green-winged equine lying on the floor, body covered in cuts and wings drooping at their sides.

Panicking, Dr. Mario rushed over to help.

“Wait!”

The winged equine turned to face Dr. Mario and he screeched to a halt. Multi-colored snot ran down their face, dripping onto the floor. Their eyes were red and puffy and it looked like they were having trouble breathing. The most horrifying part, however, was their hoof. Or, rather, the human fingers that were sprouting from the bottom— an effect of the yellow virus, Weird, no doubt.

The equine lunged at him and he quickly dodge-rolled out of the way. They shot straight for the princesses at breakneck speed.

“Watch out!” Dr. Mario called.

Luna’s horn lit up and the equine froze in midair, surrounded by a blue nimbus. Their hooves slapped to their sides as their entire body went rigid. The equine made no negative reaction to being caught. On the contrary, when Dr. Mario came around to join the princesses, a ghost of a smile had crossed their muzzle.

“The viruses must be adapting better to pony biology than humans,” Dr. Mario observed.

“I will inform my guards to erect a second barrier around the castle itself,” Celestia said, and disappeared in a flash of light.

“I must concentrate on maintaining my hold on her,” Luna said, nodding toward the equine in her magical grasp. “Can you administer your megavitamins with her like this?”

Dr. Mario began unscrewing the cap off a bottle. “Open their mouth, please.”

The equine’s mouth opened wide.

Dr. Mario took off the cap and spilled a small handful of megavitamins into his palm— roughly an even distribution of all three colors. He stepped forward and reached his hand up to the equine’s mouth. The fear that they could sneeze snot all over him was justified; in a situation like this, he would prefer to wear a biohazard suit, but he wasn’t even sure that those existed in this world. The equine didn’t struggle or squirm as he tilted the pills into their mouth before it snapped closed.

“Please swallow, little pony,” Luna said. “Take as much time as you need to build up your saliva.”

The ‘pony’s’ mouth began visibly shifting as she followed Luna’s instruction. She stopped a minute later.

“Have you swallowed them all?” Luna asked just as Celestia reappeared in another flash of light.

The pony nodded weakly.

“Good.” Luna turned to Celestia. “We will need to keep her quarantined to be safe.”

“Right,” Celestia said with a nod. “The second barrier is up, but I’m afraid I have some bad news: It seems the Primary Virus has indeed spread rapidly across the city, according to reports from our guards. They are currently preparing some biohazard suits for us.” She turned to Dr. Mario. “We have suits in a smaller size, but they’re made for ponies, not humans, so yours might be hard to move around in.”

Dr. Mario flashed her a thumbs up and smiled. “No worries.”

“Before we do anything else, however,” Luna spoke up, “we should educate you on the different types of ponies as well as what they’re capable of, considering what we just witnessed.”

Dr. Mario nodded his agreement.

“I must say,” Celestia spoke up as a wistful smile crossed her lips, “it’s a shame we couldn’t meet under better circumstances. When this is all over, would you care to chat for a while over tea? I would love to learn about the world you hail from.”

Dr. Mario flashed another thumbs up. “Sì!”

Chapter 3

Dr. Mario fidgeted in his biohazard suit, struggling to make it fit good around his body. The princesses weren’t kidding when they said as much earlier; a part of him was worried this could become a problem once they got into the heart of the quarantine zone. The face protector they’d supplied him fit much better, which was good since the face was the most vulnerable part of the body for the viruses. He continued fidgeting with his suit until Princess Celestia summoned a rope out of thin air and began using her magic to tightly secure the suit around his body with it, earning a grateful nod from him since she couldn’t see his smile through the face protector.

He turned his gaze around the castle entrance hall, taking in the group that was gathered: both princesses, six guardsponies (three each belonging to the princesses, with Luna’s own being blue like her and with bat wings), and himself, all decked out in biohazard suits and face protectors. The megavitamin bottles were evenly distributed between all the guards and Celestia. Why the princesses wanted to come along in spite of the danger, Dr. Mario had no idea, but he wasn’t going to argue with royalty. The guards were all trying to remain stoic and professional, but he could see a sliver of unease in their eyes, possibly over the princesses’ insistence for coming along.

Celestia finished tying the rope and stepped to the front of the crowd, right in front of the door. She held her megavitamin bottles in her magic next to her head as she faced the crowd.

“Here’s how we’ll do this:” she started, each word coming out muffled through her face protector, “We’ll split into three teams, with two members being responsible for restraining victims while the third will administer the megavitamins. My sister, Dr. Mario and I will form one group, and our respective guards will form their own groups. We must make every pill count, and we might not have enough for every infected pony we come across. Keep close together and watch each others’ flanks. Once we’ve cleared the entire city, we will round up the victims and transport them to the hospital wing for further inspection. This is a crisis, simply put, and we must resolve it before it becomes impossible to contain.”

All the guards snapped salutes at the end of her debriefing. Celestia turned and opened the gigantic front doors with her magic. She then led everyone across the drawbridge and onto the front lawn of the castle. The forcefield was in effect, surrounding the castle in the form of a golden, transparent dome. A quick glance around showed no ponies attempting to break through the barrier. The group approached the barrier, remaining cautious even with the safety it provided. Celestia lit up her horn again and shot a beam of light at the barrier. The light expanded, creating a decently-sized hole big enough for Dr. Mario and the guards to slip through. One by one, they did so, and Celestia shut off her magic. She and Luna then teleported past the barrier, reappearing next to the group.

“Couldn’t ‘unicorns’ do the same thing to slip past the barrier?” Dr. Mario asked.

“Our magic is greater than that of ordinary unicorns,” Celestia explained.

“What my sister means to say,” Luna spoke up, “is that we have access to a special extra-dimensional passage that ordinary unicorns aren’t aware of, yet allows us to bypass this forcefield.”

Celestia made a playful ‘shhh’ sound behind her face protector, but Luna made no obvious reaction.

Dr. Mario placed a hand to his forehead, feeling overwhelmed by the oddity of it all. He still hadn’t wrapped his head around how different things were here, but the unfolding crisis was more important. There would be plenty of time for questions once it was resolved.

“Let’s get to work,” Celestia said. She gestured to her own guards. “You three comb the commercial district.”

Her guards saluted again and galloped off down the road.

“You three comb the outskirts of the city, and be extra vigilant,” Luna said to her own guards.

They similarly saluted and flew off in the opposite direction.

“We three will be taking the residential district,” Celestia said. She turned to Dr. Mario. “You aren’t familiar with the layout of the town, so be extra sure to stay close to us.”

“Okie Dokie,” he replied.

The three of them fell into step side by side as they exited the castle grounds and onto the dirt road leading to the city. Looking at the city, Dr. Mario was impressed by the architecture of Canterlot. Grand spires boasting a wide range of bright colors rose above smaller, yet still ornately designed shops and residential houses while colorful flags stood atop, waving in the wind. The dirt path gave way to a cobblestone road ahead leading into the city. A look back to Canterlot Castle made Dr. Mario feel insignificant under its towering grandeur.

Looking to the right, his jaw dropped at the view. Lush, grassy plains stretched out beyond the mountain, broken up by a couple of rivers running into forests that touched the horizon. A couple of quaint-looking settlements dotted the landscape and a glance up revealed, to his shock, a city in the clouds! The distant forms of pegasi flying to and fro could be seen within the city’s cloud walls. Everything was so beautiful and picturesque that his heart was filled with childlike awe the entire walk to Canterlot proper.

Then they crossed the threshold into the city itself and Dr. Mario felt his wonderment evaporate and his body tense. It looked like a hurricane had blown through. No ponies were strolling about. Shopping bags and papers and other kinds of belongings were strewn about the streets as if a mass panic had taken place, which honestly wasn’t outside the realm of possibility. Everything was quiet; not even birds were chirping. The city itself felt dead. There should’ve been signs of life, however brief, but there was nothing, not even creatures other than ponies. The elaborate architecture Canterlot boasted made its current state of a ghost town all the more unsettling. A gust of wind blew a piece of paper like a tumbleweed in front of them, further adding to that analogy.

“Could the entire city be infected?” Luna asked to no one in particular.

“Possibly,” Celestia replied. “Or perhaps ponies have barricaded themselves indoors?”

Dr. Mario glanced up toward a window in a nearby building that might have been a library judging by the book picture above the front doors; there weren’t any signs of a barricade from inside. He hoped Celestia was right, regardless. Something caught his eye as he brought his gaze back down; a flicker of movement in the alleyway next to the building. He trained his gaze there, spying a mouse crawling out of a hole in the wall; a ventilation opening from the looks of it.

“Look,” he said, pointing toward the mouse.

Celestia and Luna stopped and trained their gazes on the mouse. “Can you tell it’s infected?” Luna whispered.

“We haven’t seen-a anything living yet,” he replied.

The mouse noticed them as it scurried out of the alleyway, stopping to stare at them. The air filled with tension as they stared each other down. Moments passed with neither side moving a muscle. Dr. Mario studied the rodent, trying to find any sign that it might be infected, but he couldn’t find anything, which wasn’t surprising since he wasn’t a veterinarian. The symptoms of the Primary Virus were the same across every sapient species back home, however, so the fact that the mouse wasn’t blowing multi-colored snot was a good sign, at least.

The mouse broke its gaze away from the three of them, looking back at the ventilation opening for a second before scurrying off down the street. Everyone watched it go until it disappeared around another building before looking back at the ventilation duct it came through.

“Could there be some ponies inside?” Luna asked.

“I believe this warrants further investigation,” Celestia said.

She took off into the air and flew towards the building. Luna followed right behind while Dr. Mario waited at the entrance to the alleyway, cautiously glancing over his shoulder every other second. Celestia and Luna moved from window to window, peering inside and even knocking on the front door. Dr. Mario tried shouting into the ventilation duct but heard nothing in return. If he had a flashlight he could check to see if the mouse had left any multi-colored presents inside; he should’ve grabbed a few more things from his workspace in hindsight.

“None of the windows are boarded up,” Celestia reported once they returned to him. “Perhaps we’re mistaken to believe there are ponies inside.”

Luna glanced at the building. “This is the library. In the event of a panic, I would like to believe some of our little ponies would flee to a public building such as this one. Perhaps we should teleport inside?”

Celestia looked unsure. “Maybe we should—”

A heavy flapping sound from above silenced her. Everyone looked up to see the tip of a red wing disappear over the library’s rooftop.

“Do not be alarmed, little one!” Luna called. “We possess a cure to the sickness ravaging our fair city. If you are feeling unwell, please come to us!”

Moments passed without a response. All three of them kept their eyes glued to the rooftop, waiting for somepony to show themselves. A full minute passed and still, no one did. A sinking feeling settled in Dr. Mario’s stomach and he unscrewed the cap off of one of his bottles and placed the rest in his suit’s pocket. He poured a few megavitamins into his hand and clenched it tightly, bracing himself.

A light clop sounded from behind them. They turned to see a blue earth pony standing at the entrance to the alleyway. Their face was obscured behind their light green mane while their tail twitched almost spasmodically and covering their mouth was a thick layer of multi-colored snot.

“Please relax, Miss,” Celestia attempted to soothe. “We are here to help. Stay perfectly still and we will provide you with a cure to your sickness.”

“I don’t-a think they’re listening, Princess,” Dr. Mario said.

“What do you mean?” Luna asked.

Before he could give an answer, there was more heavy flapping from above. They looked up to see two pegasi, one red and one green, dive-bombing them, faces coated with multi-colored snot and eyes glazed over.

Chapter 4

Celestia’s and Luna’s immediate reaction was to take off into the air, away from the incoming pegasi, who quickly changed direction and pursued them. Panicked expressions splitting their muzzles, the sisters lit up their horns and teleported, reappearing atop the library’s roof and leaving their pursuers momentarily confused. At the same time, the earth pony charged towards Dr. Mario, jumping at him with her hooves outstretched. He dodge-rolled out of the way just inches away from her, landing on his feet and facing his opponent with a steeled gaze. Something felt off about these ponies. Granted, he barely knew anything about this world and its peoples, and these ponies could just be so eager for help they aren’t considerate of others’ well-being. Or, maybe, they weren’t fully conscious of their actions…

“Dr. Mario!”

He briefly glanced up to see Celestia and Luna with their horns aglow, their pursuers each wrapped in the colored nimbus of their respective magic. They were struggling fiercely, trying their best to break free like fish caught on a hook.

“These two are proving to be exceptionally strong!” Luna called to him. She was visibly straining to keep a grip on the pegasus in her magic grasp. “You must defend against the third pony by yourself!”

Dr. Mario nodded. He readied his megavitamins as the earth pony turned to face him. Her tail continued twitching as did her ears. Her leg raised and hesitated for a moment before scraping the ground. The movement was awkward and labored as if their leg was broken and the action was challenging to perform, but her face remained blank, giving no indication it was painful in the least. He took note of this.

She charged at him, but this time Dr. Mario didn’t dodge. He put his shoulder in front, letting the mare ram it and putting all his strength against her. She proved strong, pushing him back along the cobblestone with ease; he could feel the rubber of his shoes rip and tear under the friction. They came to a stop after a few moments, locked in a stalemate. Dr. Mario’s body trembled, struggling to match the earth pony’s incredible strength. He reached his hand underneath his other arm and used his gloved fingers to try to pry their mouth open, but they refused to budge. He couldn’t cure them like this.

“Help… me.”

Dr. Mario’s eyes bulged. She had spoken to him! Her voice was strained like the words were a struggle to croak out. He glanced down at the pony’s blank face and was surprised to see a glimmer of awareness in them. At the same time, he felt the mare’s force against him weaken slightly. He seized the opportunity and moved his megavitamins toward her mouth.

“Don’t... want to... do this.”

The mare broke the stalemate and jumped back. The two of them stared each other down, unmoving. Her words played over and over in Dr. Mario’s mind. The way she was acting made it sound like the viruses had some degree of control over her, which was incredulous because nothing of the sort had happened to any victims back home in New Donk. But the ponies had already proven to be more ideal hosts than humans, so maybe this was what they could achieve at full strength. But how could that be?

He didn’t have much time to think about this as the mare lunged at him again and he dodge-rolled again. He grimaced. He couldn’t think of any way to make the mare open her mouth without her possibly biting into his suit and potentially ripping it, exposing him to infection from the Primary Virus. The mare attacked him again and he dodge-rolled again. Over and over this repeated without either making any progress in subduing the other. But Dr. Mario could feel himself tiring out; sooner or later his stamina would deplete and the mare would get the jump on him.

After dodging another attack Dr. Mario glanced up to the princesses again. They were still struggling to subdue their own attackers, but it was clear they weren’t in danger of being overpowered. Celestia met his gaze for a brief moment before Dr. Mario was forced to dodge another attack from the mare.

“Dr. Mario, please listen to me!” Celestia called.

He didn’t turn to face her, but he raised a hand up to his ear to indicate he was listening.

“I applaud your concern for the safety of our subjects, and I know that you seek to do no harm unto them. But right now we need to cure them by whatever means necessary! Do what you must!”

Dr. Mario took a moment to let her words sink in before he breathed a deep sigh. “Okie Dokie.”

The mare charged again, but he didn’t dodge again. Once she was close enough he shot forth his hand and grabbed their neck, eliciting a surprised gasp from her as she stopped in her tracks. Dr. Mario then hooked both his arms around her upper body and, with a measured amount of force, slammed her to the ground. A sharp exhale left her mouth as the wind was knocked out of her, rendering her immobile. Wasting no time, Dr. Mario reached down and pried open her mouth before forcefully shoving the megavitamins inside, then closed it and held firm. The mare’s eyes widened and she began struggling, but Dr. Mario put the full weight of his body on her, keeping her still.

“Swallow, per favore,” he asked.

The mare stopped struggling. She weakly nodded and began shifting her mouth to build up saliva. She continued this for a few seconds before visibly swallowing. She opened her mouth to show she’d swallowed them all and Dr. Mario nodded before getting off of her. She stayed on the ground, probably too tired to move anymore.

“Excellent work, Dr. Mario!”

He turned to see Celestia and Luna descending towards him with their pursuers still trapped in their magic.

“You truly are a warrior, Dr. Mario,” Luna complimented as they touched down. “I have borne witness to many powerful warriors throughout my extended life, but never have I seen one of your stature fight with the strength of ten earth ponies. It is most impressive.”

Dr. Mario felt a blush creep across his cheeks as he sheepishly rubbed the back of his neck. “It’s-a nothing special, Princess.”

They spent the next minute forcing the remaining two ponies to swallow some megavitamins. With all three of them partially cured, they waited until they’d regained some of their strength before they began interrogating them.

“It happened… so fast,” said the red pegasus, another mare, weakly. “Everything feels so faint… so distant… Can’t remember much…”

“I understand, little one,” Celestia soothed. She turned to the green pegasus, a stallion. “What can you tell us?”

Slowly, weakly, he lifted his hoof, pointing towards the library. He sounded much less tired when he spoke. “There’s a large group of ponies in the basement; about a few dozen or so. There’s bound to be more clusters spread throughout the city, hiding.”

“I see… Thank you.” Celestia turned to Luna and Dr. Mario. “I’ll scour the rest of the city by myself and leave you two to the library.”

“Will you be okay, Sister?” Luna asked.

“I promise,” Celestia replied. “And I trust you wholeheartedly, Dr. Mario. I know you’ll help us save our subjects.”

Dr. Mario flashed her a thumbs up. Nodding, she spread her wings and took off into the air without another word, quickly disappearing over the surrounding rooftops.

“My sister has always been a better judge of character than myself,” Luna commented. She turned to Dr. Mario with a smile. “The fact that she wholeheartedly trusts you, despite only knowing you for a few hours’ time, says a lot about what kind of a person you are.”

“What about you, Princess Luna?” he asked.

She appeared to think over her answer for a moment before replying, “I will say this: I wish there were more ponies a thousand years ago that combined the qualities of a warrior and a healer like you do.”

Dr. Mario blinked, confused by one specific part of her reply. “A thousand years ago?” She said it as though she’d lived during that time.

But Luna had turned her attention to the library, looking down at where the basement was. She levitated her bottles into her suit pocket. “Well then, let us brave this threat together.”

She lit her horn and Dr. Mario was blinded by the signature white flash of teleportation. The light cleared from his eyes after a moment and he rubbed away the remaining spots swimming in his vision before he realized he was in complete darkness.

“Princess?” he said.

“I am beside you,” she replied.

A soft moan sounded from somewhere in the darkness, making Dr. Mario’s neck hair stand on end. The space beside him lit up and he turned to see Luna’s horn glowing with a brilliant blue light that easily lit up the space around her. More moans sounded as she expanded the light to encompass the entire room. A sharp gasp sounded from both of them as the light washed over shelves lined with books with ponies lying against them, sick in the face with multicolored snot coating their bodies. Puddles of snot littered the floor all around the room. Off in one corner were a couple of creatures that looked to be half eagle and half lion, but their limbs were visibly changing into human arms.

Dr. Mario shifted his foot, only to step in something wet. He looked down to see he’d stepped in a puddle of snot trailing from an elderly unicorn a short distance behind them with her eyes closed and breathing laboriously.

“Mamma mia.”

Chapter 5

The hardest part about caring for all the sick ponies gathered in the library’s basement wasn’t the threat of being ganged up on; on the contrary, for whatever reason, these victims were far more docile than the ponies before. Having to maneuver around copious puddles of snot wasn’t particularly bad, either, even the few times Dr. Mario or Luna accidentally misstepped and got their suit-covered limbs covered in it.

The constant moaning was enough to drive them near insane.

They had started with the victims closest to them, politely asking each one to open their mouths with Luna resorting to her magic for victims that either couldn’t hear or were too afraid to take the megavitamins. They had counted all the victims in the room and divided the megavitamins accordingly while setting aside a bunch for a potential later emergency; an entire bottle’s worth.

Every other second, some pony would moan in agony from the darkness around them. For a while it was bearable, but as the minutes went by it became increasingly grating to the point where Dr. Mario would instinctively cover his ears with his hands every time it happened. Similarly, Luna would fold her ears back whenever a pony moaned. He asked at one point if she could summon any earplugs, to which she replied that she had some that fit her own ears, but not his and that it wouldn’t be fair for she alone to be spared the agony. Dr. Mario was impressed by her selflessness.

They persevered, however. Slowly but surely, they treated every victim without much hassle. The two standout creatures — ‘gryphons’ as Luna called them — put up some fuss about accepting help from ‘a weirdo alien’, only to shut up when Dr. Mario unceremoniously shoved the megavitamins in their beaks.

“Was the outbreak in your own world quite this bad?” Luna asked him at one point.

He shook his head. “No, and I’m-a glad it wasn’t after seeing all of this.”

The last pony to cure was a yellow unicorn stallion splayed in a far corner of the room. The last of the first bottle’s megavitamins were administered to him and he managed to face them with healthy, lively eyes.

“Thank you,” he croaked.

“We are happy to aid our subjects in such a time of crisis as this.” The pony started to get up but Luna gently pressed her hoof against his barrel. “Please don’t move. Further help is on the way, but for now please rest.”

“My daughter…” He lifted a hoof, pointing it behind them. “She’s gone down there.”

Dr. Mario and Luna turned behind them. Luna shined her horn light, revealing a fairly sizable hole in the wall, big enough for an adult pony to fit through. From the looks of it, it seemed to be deliberately made by a forceful impact.

“Did your daughter really make that?” Dr. Mario asked, surprised.

The stallion nodded. “The walls must be weakening. There’s no way she could break it through all on her own. I tried to stop her, but she wouldn’t listen to me. I don’t know how she knew there was something on the other side or why she even wanted to go that way.”

Dr. Mario said nothing in response, losing himself in his thoughts. A theory was forming in his brain, but it wasn’t the least bit favorable, and it would certainly make the situation more complicated if true.

Luna stepped over to the hole and shined her light through. “There’s a tunnel here,” she announced.

Dr. Mario joined her. Sure enough, a brick tunnel extended into the darkness on either side. The brickwork was loose and faded like it was centuries old. The air felt musty and likely would’ve stunk if his nose wasn’t covered by the face protector. Cobwebs littered the corners and a few bugs crawled across the floor in front of them.

“This looks to be part of the old Canterlot sewage system, built during my absence,” Luna remarked. A sharp gasp sounded from her and Dr. Mario looked up to see panic filling her eyes. “The reservoir!”

“What?” Dr. Mario said.

“This tunnel might lead to the reservoir connected to the Canterlot Falls, which itself leads all over Equestria!” Luna explained, fear gripping her voice. “If the viruses get into the reservoir, they could easily spread all over Equestria!”

“What about-a the forcefield?” Dr. Mario asked.

Luna shook her head. “It only extends above ground, and is only meant to keep ponies from getting in or out.” She stepped into the hole. “I must hurry!”

“I’ll go with you, Princess.”

“No, Dr. Mario, you go and fetch my sister. Tell her what is happening and catch up as quick as you can. I will need to use my magic to protect the reservoir from these microscopic monstrosities.”

“I doubt-a you can handle these viruses on-a your own.”

Luna turned to him with a soft, confident smile. “Perhaps, but I cannot risk Equestria at large falling prey to this Primary Virus. Join up with me as quick as you can; I look forward to being able to fight alongside you.”

She didn’t wait for him to reply. She took off galloping down the tunnel, her horn’s light indicating where she was before she turned a corner and the light gradually faded away before disappearing entirely.

Dr. Mario stared after her for a moment before sighing and turning back into the room. He walked a few steps before a thought struck him.

“How do I get-a outta here?”

The farther Luna galloped down the tunnel, the greater her fear that it was connected to the reservoir grew. Every turn she made brought her closer to the general direction where she knew the reservoir was. She came to a couple of intersections but always chose the direction leading to the reservoir, just in case the viruses managed to figure out which way to go. That fear dwarfed the fear that the infected filly might suddenly leap out of the darkness in front of her horn’s light, but she mentally prepared herself to react suddenly in case that happened.

For a short while, everything was silent save for her breathing and her rapid hooffalls. A few times she thought she heard hoofsteps coming from ahead or behind her and she briefly stopped to call out, only to receive no response, deciding she was just hearing things. At one point she thought the filly would be scared to hear her approach and so used a spell to mute her hooffalls. No matter what was wrong with the filly, they were still young, and therefore, easily frightened.

Then a sound reverberated off the walls from the darkness ahead. Luna perked her ears, fully attentive, and listened. The sound was too faint to identify at first, but as she moved forward it became clearer until her heart dropped when she realized what it was: running water. She picked up her pace until she decided to throw caution to the wind and dived into a quick succession of teleports, stopping once she found herself in an open chamber. A large pool of water was built into the floor in front of her with a canal running through it. Sunlight filtered into the chamber from an opening downstream the canal, through which Celestia’s sun could be seen hanging over the distant horizon; she wouldn’t have a chance to lower it until this crisis was resolved.

She swept her gaze all around the room, finding no trace of the filly; she hoped the viruses hadn’t already gotten into the canal. She quickly erected barriers covering the pool, the canal, and an extra durable one for the opening leading outside, making sure that it extended all the way beneath the water’s surface. She was fairly confident this all would be enough to prevent the viruses from escaping.

“What is this world we’re in?” came a small, playful voice from behind her.

Luna froze up. Quickly, she lit her horn and shone it behind her. The light revealed a pair of magenta, glazed over eyes and the fakest smile she’d ever seen on a pony. She expanded the light’s reach, revealing a small earth pony filly looking up at her; her pink coat and green mane were barely visible underneath the thick layer of multicolored snot coating them. The filly had a set of nasty-looking bruises covering her left shoulder, swollen and obviously caused by immense force; quite possibly from ramming the wall from before. A look down showed her little hooves were cracked and bleeding in a few places, yet she showed no signs of agony.

“Why didn’t I run into you before?” Luna asked, not having registered the filly’s own question.

The filly said nothing for a short while, just staring at Luna with that unnatural smile. Luna felt a chill run down her spine. Something was definitely off about this filly, that much was obvious, but she couldn’t let any weakness show. Right now, she had the upper hoof; all she had to do was not back down.

“What is this world we’re in?” the filly repeated.

This time Luna processed the question. She was confused at first, but then a disturbing thought rose to the surface of her thoughts, one that sent another, stronger shiver down her spine.

“Am I speaking to the viruses?” she asked, forcing her voice not to quiver. The situation just turned more complicated and the filly’s life was potentially in actual danger. “You must let the young one go. Now.”

A different voice came from the filly, this one more snarky. “You’re not the boss of us!”

Before Luna could answer, a third voice, this one melancholy, came out of the filly’s mouth, “We just want to be free. Please let us go outside.”

“That will not be happening,” Luna replied with conviction. “How are you possessing the body of this filly? Mere viruses should not have such an ability.” She didn’t know this for sure; they were from another world, but Dr. Mario never described anything like this happening in his experience with them.

When the filly spoke this time, all three voices replied in unison. “What you call ‘magic’... It’s allowing us to multiply exponentially. It allows us to complete our mission…”

Luna quirked an eyebrow. Their ‘mission’? Did they have someone they answered to? That didn’t make any sense, but then again, it was just another item on that particular list regarding these viruses.

“Whatever your motives, you are putting the well-being of me and my sister’s subjects in jeopardy,” she stated, again with conviction. “I order you to release the filly from your control or you will face dire consequences.”

The filly looked contemplative for a moment before she let out a simple, “Nope,” and lunged at her. She moved so quickly, almost in a blur, but Luna reacted fast enough; she shut off her horn light and grabbed the filly in telekinesis.

The filly struggled wildly in her magical grasp, thrashing her hooves about every which way like an animal caught in the mouth of a predator. She stopped at one point to flash Luna an annoyed glare, to which Luna stared nonplussed right back. This filly wasn’t any stronger than the adult ponies from earlier; she had no chance of breaking out of her magic grip.

“Malevolent invaders such as yourselves have no place in this world,” she said. “If you refuse to let this filly go, we will have no choice but to exterminate you like the vermin you are.”

The filly stopped thrashing to level a bemused expression with her. “You were going to do that anyway.”

“... We would be more than willing to spare your lives seeing as you have the capacity to choose not to do harm unto our subjects. Would you agree to that?”

The filly didn’t answer. Instead, she reared back and blew a giant glob of multicolored snot all over Luna’s biohazard suit. The sudden action surprised her, but her surprise quickly gave way to annoyance.

“This accomplishes nothing.”

A playfully sinister smile split the filly’s muzzle. “Does it?”

Luna looked confused for a moment before her ears perked at a new sound, one that froze the blood in her veins.

Ripping fabric.

Chapter 6

Navigating the library was more time-consuming than Dr. Mario would’ve liked, which was to say, even a little. Finding the door out of the basement was easy enough and he dashed up the flight of stairs beyond to the ground floor, only to find himself in a dimly lit hallway without any windows and several doors on either side. Furiously, he began throwing them open one after another hoping to find a window, but always found paper-littered desks, shelves of books, and a vending machine filled with brand drinks he wasn’t familiar with. He wished Luna hadn’t been in such a rush and had teleported him outside, but what was done was done. He continued checking doors until he finally found one that led into the main public area on the other side of which stood the front doors. He dashed over and practically jumped outside.

The streets of Canterlot were just as still and silent as before he’d entered the library. Over and over, he called out Celestia’s name as he dashed down every single alleyway and main street. Infected ponies could’ve heard him and jumped out to ambush him at any second, but the possibility of the viruses escaping Canterlot was a far greater worry. He still had a full bottle of megavitamins left in case things got hairy, anyway.

Finally, as he was nearing what must have been the train station judging by the stationary, pink engine across the platform, he heard a pair of great wings flapping overhead and looked up to see Celestia descending towards him; trailing behind her was her trio of guards.

“I had no idea you could shout so loudly, Dr. Mario,” she said as she touched down in front of him, followed by her guards. “How fares my sister? Why are you here?”

“There’s a filly that’s-a become possessed by the viruses,” Dr. Mario explained. “Luna is sure they’re heading for the reservoir through an old sewage system underneath the library. She wanted me to fetch you to get-a your help.”

Celestia’s eyes briefly flashed with surprise before she regained her calm demeanor and nodded. “Then let us hurry.”

She lit her horn and a flash of light filled Dr. Mario’s vision. Once it cleared, he saw the five of them were back in the library’s basement. All the victims he and Luna had cured were still sprawled around haphazardly, but looking far less tired and sickly than before, indicating the megavitamins were working.

Celestia turned to her guards. “Start getting everyone back to the castle’s hospital wing and make sure they get the utmost level of quarantine. Dr. Mario and I will follow after my sister.”

The guards all snapped a salute and got to work.

Dr. Mario led Celestia to the hole in the wall. She studied it with interest for a moment. “I remember when this was built about three hundred years ago. Clearly, we will need to conduct some renovations after this is all over. I wonder how this filly could know of this?”

“I don’t-a know,” Dr. Mario said. “But I have a hunch she isn’t doing this by choice.”

Celestia turned to him, confused. “What do you mean?”

“These-a viruses are sapient, that much is obvious by now,” he explained. “That one pony I fought-a with said she wanted help and she didn’t want to do what she was-a doing. I don’t know how, but the viruses might be able to control the actions of those they infect.

Celestia’s eyes bugged at hearing that theory. “Truly!?”

“It’s just a theory, but it’s the only one I can come up with.”

“Then we must make haste and aid this filly before the viruses are able to truly harm her.” She stepped through the hole into the tunnel. Dr. Mario followed right behind.

“Before-a we go, I have one question, Celestia.”

“Yes?”

“How long have you been alive?”

“Let’s just say I’m an overly-seasoned ruler,” Celestia said with a cheeky smile. “I’m also quite a good runner, so let me do this—” She lit up her horn and Dr. Mario gasped as he was pulled up off the ground, floating through the air before being lowered onto Celestia’s back. Next, she lit up her horn to illuminate their surroundings. “Hold on tight so you don’t fall off,” she advised.

Dr. Mario heeded her advice and wrapped his arms tight around her withers. Celestia folded her wings against her sides, lowered her head and scuffed her hoof against the tunnel floor. She then took off like a bolt of lightning, shooting so fast that Dr. Mario almost lost his grip on her. The tunnel walls whizzed past at breakneck speed under her horn’s light— after a short while, looking at them made Dr. Mario’s head swim, so he closed his eyes. They came upon a few intersections, at which points Celestia would stop for a moment to look between them before picking a direction and galloping like the wind again. Dr. Mario was too busy holding on for dear life to enjoy the thrilling sensation even a little.

Finally, the faint sound of running water reached their ears. A source of light illuminated the tunnel up ahead, rapidly growing bigger as they approached. They came out into a large chamber and Celestia stopped, letting Dr. Mario hop off her back. They both took in their surroundings. A canal ran the length of the chamber, leading into a large pool before continuing on the other side towards an opening that led to the outside, but transparent, midnight-blue barriers covered all the water.

“Luna!” Celestia called out.

“Sister!”

They turned to see Luna standing against the wall next to them, behind another barrier with her biohazard suit oddly torn to pieces next to her. A pink earth pony filly with a green mane was pounding against the barrier with her tiny little hooves, trying but ultimately dealing no damage. She stopped hammering against it to turn to them. A creepy, playful smile split her muzzle as she looked over Celestia before dipping when she noticed Dr. Mario.

“You,” she said with obvious disdain.

“You have nowhere to run to, viruses,” Celestia said. She lit her horn and cast a golden barrier over the entrance to the reservoir.

The filly laughed. “Your magic lets us multiply exponentially. Enough that we could take over your motor functions and force you to let us escape to the outside world through here.”

“And how did you find out about this place?” Celestia asked.

A new voice came from the filly, this one snarky rather than playful. “We sent out scouts to sweep the city when we escaped from him—” she finished with resentment clear in her voice as she pointed at Dr. Mario.

“Nothing about you viruses is normal, it seems.”

“It took you that long to realize this? And you’re supposed to be the ruler of this world?”

Celestia didn’t let the insult faze her. Instead, she, along with Dr. Mario, stepped forward with their bottles primed. “Would any efforts to negotiate fall upon deaf ears?” she asked. “Could you not be persuaded to cease your transgressions against my people?”

The filly laughed. “Never! We must spread far and wide, as is our mission!”

Mission? Dr. Mario was almost taken off-guard by the statement, but it was already beyond clear that these viruses were anything but normal. Right now, however, neither their motives nor origins mattered; they were a threat to the health of everyone in every world they entered, and so had to be stopped at all costs.

“I’ll-a use the megavitamins, Celestia,” he said.

Celestia nodded and put away her own bottle. She then lit up her horn and grabbed the filly with her magic, lifting her up into the air. Strangely, the filly put up no resistance. The sinister, knowing smile she wore was out of place, making Dr. Mario uneasy as he moved forward.

“Sister! Dr. Mario!” Luna called from behind her barrier. “It’s a trick!”

They both looked at her curiously. In the moment they were distracted, the filly reared back and blew a giant glob of multicolored snot at Dr. Mario. Pure, base instinct took over and he jumped out of the way, keeping his hand firmly clutched on the bottle. The glob of snot sailed through the space of air where he had been and splashed across the front of Celestia’s suit. The impact startled her, but she didn’t look fazed.

“Sister! Get out of the suit!” Luna cried, panic filling her eyes. “Get behind the barrier where it’s safe!”

Again Celestia looked at Luna curiously. Then her ears perked up as a faint sound of ripping fabric filled the air around her, growing louder with each second. Her eyes bulged and, in a flash, she teleported out of her suit, reappearing next to Luna behind the barrier, leaving the filly to fall back to the ground on her hooves. Everyone watched as the suit fell to the ground where it immediately began tearing at the seams as though by an invisible force. Pieces ripped apart and were cast aside like paper shreds. In little more than two minutes, the suit was a shredded mess beyond repair.

Dr. Mario could only watch, stupefied, at the display, before he was snapped back to reality when the snot merged together and began creeping across the floor towards him. He sprang into action, unscrewing the cap off his bottle and pouring a small handful of megavitamins into his palm. He carefully arranged them by color before dumping them onto the viruses. To his relief, the megavitamins still worked, quickly and effortlessly killing them; a part of him had grown worried the viruses were becoming strong enough to resist the megavitamins.

The filly locked a spiteful gaze onto him. When she spoke, it was with three different voices layered together: playful, snarky, and melancholy.

“You are quite the nuisance. What will it take for us to be rid of you for good?”

Dr. Mario primed some more megavitamins. “I’m-a never gonna back down,” he stated.

“How annoying.” The filly reared back and blew another glob of snot towards him. Dr. Mario dodged and proceeded to use the megavitamins on it just like before. The filly tsked. “You won’t win!”

She took off in a gallop, charging him in a little pink blur. He reacted on instinct yet again, jumping out of the way, landing on top of the barrier covering the pool. The filly charged him again, missing, but by a shorter distance this time. This couldn’t last forever; he needed to come up with a strategy to subdue the filly. Getting in close was extremely risky, and the princesses would have to leave themselves exposed in order to help.

He cast a brief glance their way while the filly was reorienting herself; they looked concerned and even a little upset, probably because they didn’t think they could be of any help in the fight. It was strange to think about; two all-powerful alicorns powerless against something as small as the Primary Virus, and he, a single human doctor, who couldn’t teleport or fly or use magic of any kind, only had his limited human strength to carry him through this fight. His biohazard suit had lost its purpose if the viruses were able to tear it apart, but it would at least protect him from a single hit.

A spark of an idea flitted through his mind. It was simple, yet dangerous, but it was all he had right now so he held onto it. He didn’t have much time to convince himself it was a bad idea as the filly charged again. This time, he held his ground, and the filly bit into the leg of his suit, pulling with all her might to tear it apart.

“Dr. Mario!” the princesses cried in unison.

The fabric on his suit was ripping surprisingly easily under the bite of a creature without canines, but then again, the viruses themselves were somehow able to rip it apart. He quickly bent down and hooked an arm around the filly’s body. He pulled with all his might while she struggled to break free. He set down his bottle to hook his other arm around her body. With the added strength, he managed to pull the filly off of him; a giant piece of his suit came off in her mouth which she spat out.

“Let us go!” she cried.

Dr. Mario moved fast. He removed one arm from her to reach down and pick up the bottle. The filly almost broke free of his grasp, but he held firm as he pressed the bottle up to her mouth. The filly’s eyes bulged at the sight of the megavitamins contained within and she shut her mouth, thrashing even harder in his grip.

“I could use-a some help!” he called to the princesses.

The princesses teleported from behind the barrier and next to him. Luna lit her horn and the filly’s body was enveloped in a blue nimbus and she stopped thrashing in his grip, allowing Dr. Mario to release his arm from her while keeping the bottle pressed against her mouth. The filly reared her head back, ready to blow another glob of snot, but was thwarted when Celestia erected a barrier covering the filly’s head sans mouth and the snot impacted the inside of it. Luna forced the filly’s mouth open and Dr. Mario carefully tipped her head back and gently dumped a fair amount of megavitamins into her mouth, her eyes filled with pure terror all the while. Once the megavitamins were in place, Luna forced the filly’s mouth shut. A moment passed and it was obvious the filly wasn’t making an attempt to swallow the megavitamins.

“Whoever you are, my little pony,” Celestia soothed, “you must still have a modicum of control over your actions. Please fight against the viruses’ influence and swallow the megavitamins. I believe in you.”

The filly’s eyebrows lowered in a show of defiance and she shook her head furiously.

“If she was asleep I could enter her dreams and perhaps give her the motivation to fight against them,” Luna remarked.

“If only we knew how the viruses are controlling her I might-a have some medicine to subdue them,” Dr. Mario said.

Celestia looked up in thought for a while, before saying, “I have an idea.”

She disappeared in a flash of light. In the minute she was gone, Dr. Mario’s mind ran with all kinds of fantastical possibilities as to what her solution could be. As such, it came as a surprise when she returned with nothing more than an ice pack.

“Set her down please,” she said.

Luna gently placed the filly face up on the floor while Dr. Mario kept the bottle over her mouth. Celestia placed the ice pack over the filly’s forehead while her eyes bulged with terror. She visibly tried to struggle under Luna’s magic, only for her body to relax a few seconds after the ice pack was applied and her eyes went blank. Luna released her magic hold, but the filly made no attempt to get back up, seemingly immobilized by the touch of the ice pack. Dr. Mario removed the bottle from her mouth, but she didn’t spit out the megavitamins.

He cast a confused glance at Celestia, to which she explained, “It was just a hunch, but keeping someone cool is how you relieve symptoms of a sickness, so it stood to reason that the viruses could be weakened by the same method. Truly, we are lucky that it worked.”

To think that a doctor could overlook such an elementary concept in the medical field of study— Dr. Mario could only laugh in response.

Celestia placed a wing over the filly’s body and began gently stroking her, “If you can understand me, my little pony, then please swallow the megavitamins. They’ll cure you, I promise.”

A glimmer of awareness came to the filly. She stared up at the three of them for a few minutes, blinking every now and then like she’d just come out of a trance. The genuine confusion in the filly’s eyes told Dr. Mario that the ice pack was working, that she was in control of her thoughts again. Then the filly seemed to realize she had something in her mouth and it shifted as she began building up saliva. A few moments later she visibly swallowed and let out a cute, relaxing breath.

“Feeling better?” Dr. Mario asked.

The filly met his gaze and arched her eyebrows. “What are you?” she asked very weakly.

“Imm’a Dr. Mario!” he introduced himself. “And I’m a human!”

“What is your name, little one?” Luna asked the filly.

“Melon Seed,” she replied. “Where’s my daddy?”

“He is safe, rest assured.”

“I don’t remember anything.” Melon Seed swept her gaze around the reservoir chamber. “What is this place?”

“We’ll explain everything later— to all of Canterlot, we promise,” Celestia said. She cut off her barrier and lifted Melon up in her magic. “For now, we need to get you quarantined and treat your injuries.”

“What does ‘quorein— quaireent—’ what does that mean?” Melon asked. “Is it painful?”

The adults all shared a laugh.

“Don’t worry, it isn’t,” Dr. Mario assured her.

Chapter 7

The princesses and Dr. Mario teleported out of the reservoir with Melon Seed and regrouped with all of their guards, who reported that the entire city had been thoroughly searched and every single infected citizen was administered megavitamins. With that, they rounded up all the guards stationed at the castle and got everypony to work bringing infected citizens to the hospital wing of the castle. Dr. Mario supervised the roundup, carefully examining each pony to make sure the megavitamins were doing their job. He also promised to stock up on extra bottles for them after he got back home in case they needed it.

“Hold still,” he told a unicorn mare who had a small amount of multicolored snot smeared across her cheek. He used a q-tip to wipe it off and placed it in an empty bottle. The q-tip twitched ever so slightly under the viruses’ influence. Once he was done, Luna erected a dome with air holes over her.

“What might that be for?” she asked him.

“I’m-a gonna take it to some scientists for study,” he explained, screwing the cap on the bottle. “It’s a good idea to learn more about-a these things in case this happens again.”

Celestia walked into the hospital wing levitating a sick earth pony stallion. She placed him on an unoccupied bed in a row of several dozen containing sleeping and exhausted ponies and erected a similar dome with air holes over him. She then made her way to Luna and Dr. Mario as three guards entered the room behind her, carrying another couple of ponies.

“We should be done just after dusk,” she said to them.

“That’s good to hear,” Luna said.

Celestia turned to Dr. Mario with a sincere smile. “Words cannot express how grateful I am for your aid in combating this alien threat, Dr. Mario. How could we ever repay you?”

Dr. Mario blushed, rubbing the back of his head. “Ah, it was-a nothing, Princess. Really, just being able to help the sick and suffering is reward enough for me.”

He held up the bottle for them all to see. The movements of the q-tip were even more visible now, lightly bashing against the inside of the bottle as the snot coating it shifted up and down accordingly; the viruses were undoubtedly furious about being trapped again.

“What do you suppose is the reason for these viruses’ sapience?” Luna asked.

Dr. Mario shook his head. “I couldn’t begin to guess. But I’ll find out soon enough once I return home.”

“Well, now that this crisis is over and done with, you have the opportunity to enjoy Equestria and all its beauty more casually,” Celestia said, smiling again. “But I suppose you’ll want to set aside some time to do so first? Even here, doctors have hectic schedules.”

Dr. Mario flashed her a thumbs up. “I’m-a gonna come back soon, don’t worry! Everything here is so different and interesting, and I could use a vacation!”

“I’m glad to hear that,” Celestia said. “There are many wonderful things to behold in Equestria, many more than can be seen in a single visit.”

“Even better!”

“Well, Luna, I do believe the time has come to bring forth the night,” Celestia said, casting a glance out the nearest window.

“What does that mean?” Dr. Mario asked, genuinely curious.

“We’ll show you,” Luna said.

In a flash, the three of them were teleported away from the hospital wing onto a balcony near the top of the castle that overlooked the Equestrian landscape all around. Dr. Mario was used to the teleportation by now and so didn’t feel disoriented coming out of it. The sun was hovering just over the horizon in front of them.

“Watch closely,” Luna instructed.

Dr. Mario nodded.

Celestia’s and Luna’s horns lit up and they closed their eyes. Dr. Mario had his eyes trained on them until he noticed the sun’s light was perceptibly dimming. Looking towards it, he was amazed to see it was lowering beneath the horizon at a speed discernible to the naked eye. A movement to its right caught his attention and he looked to see a white light rising above the horizon. The moon! More specifically, a crescent moon. Perfectly in sync with each other, the sun disappeared beneath the horizon while the moon rose high into the sky, stopping after a minute where it hung, casting its illuminating rays upon the land in the sun’s place.

The display was enough to take Dr. Mario’s breath away.

“That’s… amazing.” He turned to the princesses. “You did that with your magic?”

They both nodded.

“Even the kinds of magic back in my world couldn’t do something as amazing as that.” He placed a hand to his forehead, feeling overwhelmed. “Caspita…”

Celestia giggled at his reaction while Luna remained straight-faced but with a ghost of a smile.

“I believe now we have the time to sit down and chat,” Celestia said. “Your world must be interesting if it contains creatures such as the viruses.”

“Okie Dokie!” Dr. Mario said cheerfully.

Celestia’s horn lit and the three of them were teleported to a room within the castle. Looking around, Dr. Mario saw that it was a sitting room, lavishly furnished. A low table sat in the center of the room, surrounded by a number of plush, comfortable-looking colorful cushions. Set against one side of the room was a small, old-fashioned stove. On the table sat an empty tray with cups, plates and a teapot. In every universe, it seemed, princesses loved tea.

Luna levitated the tray off the table and brought it over to the stove and began brewing while Celestia and Dr. Mario took seats around the table. As he thought, Dr. Mario practically melted into his cushion when he sat down, letting out a deep, relaxing sigh at the comfort it afforded him; he was half tempted to ask the princesses how much he could buy it off of them, if possible. The brewing only took a couple of minutes, surprisingly, and soon enough everyone was being served tea. One whiff told Dr. Mario it was green tea; not his favorite, but he’d still drink it to be polite. He took a sip and found it to be much better than the kind he’d experienced back home and drank a bigger gulp.

They talked for about an hour or so while drinking, exchanging stories about each others’ worlds and a few about their personal lives. Apparently, the princesses really were centuries old and they had quite the breadth of stories as a result. Lots of world-threatening catastrophes occurred throughout their rule over this land, threatening the happiness and well-being of their subjects and forcing them to take up arms as heroes which usually involved utilizing a set of magical artifacts known as the ‘Elements of Harmony’. And that was in addition to the grueling task of both establishing and maintaining good relationships with foreign lands.

Meanwhile, the most interesting thing that had happened to him in recent memory was the flat tire he’d gotten yesterday on his way to work. Compared to his rather mundane life in comparison which he sometimes struggled to keep a handle on, he was impressed by how well they seemed to manage running a country for a long time while all kinds of crazy stuff happened.

“Ya know,” he said once they were done exchanging stories, “a part of me is kinda glad the viruses escaped here so I could meet you and see this world. Sorry if that makes me sound selfish.”

“That is perfectly understandable,” Luna said with a nod. “Every event, every choice, has a light and a dark side. It is good to acknowledge both.”

“What matters is that the viruses have been stopped,” Celestia said. “Now that they are, we should make the best of our meeting.”

“I agree,” Dr. Mario said.

A few moments of silence passed before Luna cleared her throat and said, “I suppose you’ll be needing to leave for the time being.”

“Yep!” he replied. “I gotta get a good night’s sleep before-a I deal with all the patients whose appointments I rescheduled.”

“Then let’s not waste any time,” Celestia said.

She lit her horn and teleported the three of them from the balcony to the supply closet containing the Window. The door was open and the bright Window stood out prominently against the nighttime darkness. As before, guards were stationed on either side.

“You are dismissed,” Celestia told them.

The guards saluted and quickly and quietly left, disappearing around the corner down the hall.

“You never did-a say why this thing exists,” Dr. Mario said, pointing to the Window. “And what’s-a one doing in my supply closet?”

“There’s a story behind that if you’d like to hear it,” Celestia replied. “It would take too long to describe it in detail, however, so a cliff notes version would be preferable.”

Dr. Mario nodded and listened as she told her story.

“A little over a year ago, myself, my prized pupil, and several people hailing from multiple universes were abducted by an omnipotent entity named Aza - 090, or ‘Aza’, for short, as part of a sadistic game wherein they placed us in many kinds of peril, forcing us to work together to survive. By the end of it all, we learned that, in reality, Aza was a mere tool used by an even higher entity named Razalon to bring us all together as a form of entertainment for the people of his universe. There are a few solicitous details I’d rather not go into, but suffice to say the Singularity was created by a higher power that seeks to use the struggles of peoples from all universes as a form of amusement.

“As for why there’s a Window in your supply closet; there were more Windows than abductees when we first found ourselves in the Singularity, and I wouldn’t be surprised if several more have appeared in there from when I was last inside.”

Dr. Mario took some time to digest everything she’d said. It was hard at first to grasp the scope of what she’d said, but the fact that she’d truncated her recounting certainly helped. The gist of everything was clear, but it was still a heavy weight on his brain. It was quite a revelation, to say the least, but he believed it fully. Now he was interested in seeing every world connected to the Singularity in addition to Equestria.

“Well, this is goodbye for now, I suppose,” Celestia said, smiling wistfully.

“Consider yourself welcome to visit Equestria whenever you desire,” Luna said proudly.

Dr. Mario nodded and stepped toward the Window. “I’m-a looking forward to it!” The princesses waved goodbye as he put a foot through the Window and he waved back. “Ciao!”

He put his whole body through the other side into the Singularity. He quickly located a Guide and asked for the Window leading to New Donk City. The guide summoned the appropriate Window and he stepped through back into his supply closet and out into his workspace. Nighttime had fallen here as well with his own world’s moon’s light shining through the window.

He sat down on the examination table to collect his thoughts, the bottle containing the viruses clutched firmly in hand. It had been a very long, very unexpected day. The Window in his supply closet was bound to be discovered at some point by the building’s contractor or his boss or someone; he wasn’t sure what he was going to do at that point, but he decided to ruminate over it at a later date. He also decided to ask for some vacation time as soon as the Primary Virus had been dealt with here so he could go back to Equestria. Truthfully, he foresaw himself having a hard time wanting to leave that magical world.

He hopped off the table once he was done thinking and looked at the bottle in his hand. Legally, he wasn’t allowed to take samples like this home, but given how easily the viruses were able to escape earlier, he had to take some precautionary measures to ensure that didn’t happen again. He strode over and opened the sink cabinet, pulling out an empty plastic bin. He set the bottle inside and carried it over to the windowsill, placing it very carefully so as to make sure it didn’t fall over.

“Safe and sound,” he said, satisfied.

He turned around, took all of two steps, and suddenly the room was filled with blinding yellow light. He stumbled forward, surprised, and wheeled around to see what was happening. The light was coming from outside. A myriad of explanations flitted through his mind; the only one that seemed at all likely was a pair of high beams on a car. Then the light blinked rapidly a few times, in quicker succession than what a car could achieve, and seemed to focus on the plastic bin on the windowsill, forming a cone-like shape.

Then, to his bewilderment, the bottle actually started levitating out of the bin into the air as if pulled up by the light. Instinctively, he rushed forward and grabbed it, only to stop and for his jaw to drop at the sight outside the clinic.

A flying saucer, about ten feet or so in length and emitting strange humming noises, hovered outside his window, the light spilling from beneath while several more lights littered the metallic hull. There were no visible windows on the hull, leaving it completely a mystery as to what the occupants looked like if there were any in the first place. The light pulled the bottle up towards the saucer, only to halt when it hit the window. It banged forcefully against the glass a few times before reeling back like a baseball pitcher and smashing through the window, shattering it and sending glass shards flying into the bushes underneath.

Dr. Mario watched as the bottle was pulled through an opening in the underside of the flying saucer. Once it was inside, the opening promptly sealed shut and, as fast as a shooting comet, the saucer zipped into the sky, quickly becoming a speck of yellow light among the stars.

Dr. Mario blinked. He stood there for a short while, his mind a scrambled mess of thoughts and emotions.

“Mamma mia.”