My Little Pony & Ben 10: Cosmic Crisis

by Calmed Equine

Rating: everyone
Tags: Adventure, Princess Celestia, Crossover, Main 6, My Little Pony: Friendship is Magic, Princess Luna, Drama, Spike, Science Fiction
Length: 3426

Ben Tennyson gets accidentally sucked down into the land of Equestria.

When a suspicious interdimensional portal opens up right in the Royal Canterlot Castle, Princess Celestia quickly invokes the Elements of Harmony to help her, only to find nothing more and nothing less than a 16 year-old male human with a mysterious technologic device on his wrist , which allows him to transform into a huge variety of powerful, extraterrestrial beings.

But that human is not the only thing that has arrived to Equestria...

Published 2017-11-08 00:40:07 UTC
Last updated 2017-12-03 00:51:19 UTC

An Unexpected Visitor

A deafening roar was heard when the doors that served as entrance to the throne room were opened wide and the six mares entered into the Hall galloping at full speed, sweating and breathing with difficulty.

"We came as fast as we could, Princess. What is happening?" Twilight Sparkle reached to say as he neared his former teacher and her younger sister, panting and trying to recover the lost air from her lungs. Their wings, fatigued by having flown many kilometers from Ponyville until Canterlot relentlessly, felt like two huge and heavy bags filled with stones. Having to load somepony who often consumed vast quantities of sugar like Pinkie Pie during the whole trip had not made things easier for her.

“Twilight!” Princess Celestia yelled with relief, hugging her former student with her majestic, big white alicorn wings. “Thank goodness you are finally here! I was starting to worry”.

"Indeed. You have arrived at the right time, Twilight Sparkle" Princess Luna replied with her usual and characteristic real accent, pointing out a certain corner of the room with her right fore hoof. "Our problem is right there".

Twilight turned his attention toward where Luna was pointing, and what she saw left her speechless. A few meters away from the thrones of the two rulers of Equestria, what seemed to be a huge portal with a multi-colored aura that was starting to expand more and more, threatening to devour the entire room on its way.

“Ooooh!” an innocent, dazzled Pinkie Pie exclaimed, bouncing on her place, “Pretty!”

“What in the hay is that supposed to be?” Rainbow Dash managed to shout both amazed and scared at the same time. Her pink, magenta eyes had never seen anything like that before.

"We have no idea” Celestia admitted, sighing in defeat. “It came out of the blue one or two hours ago, and we have made the impossible to make it disappear since then, yet we are still sensing an unknown presence coming from it”.

Twilight ignited her horn, slowly trotting right towards the mysterious, unstable energy field. Her eyes glowed with a pinkish glow and her mind began to search beyond until something stopped her for going any further, breaking her concentration and sending her back to the throne room, with her friends and the princesses behind her. Whoever that presence belonged to, it was strong, colossal and it was certainly not from a pony.

“Yes” she finally said, “I could feel it too”.

“Well, whatever it is, I must say I adore its multi-faceted color palette!” Rarity moaned, taking a look at the many colors the strange portal had started to acquire.

“Um, Rarity” Fluttershy said with deep concern reflecting on her face, “I don't think it's time to admire but rather to find solutions”.

“Oh, yes!” the Element of Generosity quickly answered, coming back to her senses with noticeable embarrassment. “I'm sorry. I think I was just hypnotized by such a beautiful-yet at the same time horrible-visual spectacle”.

"Ah don't know what ya think, Twi” Applejack hurried to say, reaching her friend and putting her left fore hoof on the lavender alicorn’s right shoulder. “But right now mah sixth sense is tellin' me that we should all stay as far as possible from that thing 'til we know what it is. N' Ah'll gladly comply”.

“You're right, AJ” Twilight said, still looking at the seemingly unstoppable portal-like energy field, then turning back to Celestia and Luna with a frown. “Maybe we should call Sunburst and Starlight for assistance. I know they are a little tied up at the moment helping Thorax with a certain delicate affair in the Changeling Kingdom, but…”

But the Princess of Friendship would never end that sentence. She was taken by surprise with the shudder of the floor. The energy field grew wider and everypony rapidly stepped back, shaking in fear.

Suddenly, what it seemed to be a giant brownish, five fingered hand came out from the energy field. Seconds later, an enormous head with light green eyes and a titanic torso followed it.

Both Rarity and Pinkie Pie screamed. Luna and Celestia adopted a fight stance, with their wings and horns ready to fight. Fluttershy instinctively hid behind a defiant Rainbow Dash, trembling and paralyzed by fear. Twilight’s mind, on the other hand, was blank. She could not comprehend what she was seeing.

"You!” she managed to affirm, “You're the presence I felt!”

"What in tarnation?!” Applejack cried out in shock.

"I don't know who or what you are supposed to be” The giant head bellowed with a strong, raspy voice, finally stepping out of the portal, revealing itself as a gigantic, bipedal talking reptile who was big enough to touch the room’s ceiling. “But you better get out of my way, or I’ll smash you all until I find him!”

Twilight had unconsciously started to shiver. Then, she remembered her manners and decided to greet their newcomer, willing to risk it all.

“Twilight, darling!” Rarity yelled. “Stop! What are you doing? Stay away from that…..that thing!”

“Don't worry, girls” Twilight said without turning back. “Trust me. I know what I’m doing. Just step aside until I tell you it is completely safe”.

Celestia and Luna looked at each other and nodded. The two princesses strongly believed in Twilight's judgement, especially after all they had experienced with her and her friends in their lives the past few years.

"Uh, well Hello!” she said, trotting to the amazing creature with both excitement and curiosity. “Allow me to introduce myself. My name is Twilight Sparkle, and as the Princess of Friendship it is my royal duty to give you the welcome to the land of Equestria! It is a pleasure, mister…”

"The name’s Humungousaur!” the gargantuan lizard roared, shaking the room with its imposing voice, “And if you don’t tell me where he is right now, I´m going to make this place fall apart in less than five seconds!”

“Uh, I’m sorry, what did you say?” The lavender alicorn asked while sweating. It was at that moment when Twilight noticed something curious in the lizard’s chest: a circular, metallic-ish plate with a green and black symbol, which reminded her a lot about hourglasses.

“You heard me, you….Whatever you are” the lizard roared once more, this time raising up his fore claws and closing them to form fists. “I won’t repeat it. Now tell me where he is hiding or else…!”

“He? Who is this “He” you are ranting so much about, ugly?” Rainbow Dash finally spit out, flapping her wings in the air and ready to attack their unwelcome visitor, only to be dragged out by Applejack, who quickly grabbed her by her rainbow colored tail with her mouth as she had done many times in the past.

“Hold yer flank, girl!” The farm mare managed to say, trying not to choke with the itchy pieces of hair on her tongue.

“Ooh, ooh!” Pinkie Pie said, hopping where she was standing. “He must be referring to Gummy! He must be his lost father!”

“Pinkie Pie!” Twilight shouted, “You're not helping!”

“Or maybe it's his north cousin!” the pink pony continued, oblivious to Twilight’s words. “Or….Unless….Ooh, ooh! I know, I know! He must be…!”

“PINKIE PIE!” Rarity finally snapped. “HUSH!”

“Oh! Oki Doki Loki!” Pinkie Pie answered, now realizing the situation.

“Thank you!” Twilight sighed relieved. Her tense muscles loosened a bit.

“Anytime, dear” the white, purple-maned unicorn replied with elegance.

“Enough talk!” Celestia announced using her royal voice, facing the brown reptile like the fearless ruler she had to show she was. “Who are you and why have you come to our kingdom?”

“Wait a minute!” The lizard spoke once more, this time with a confused look in his face. “You’re talking horses? What the hell? Then that means I´m not in Bellwood anymore!”

“Well, technically we are ponies, but…” Pinkie Pie started.

“Why did you bring me here?!” The beast started roaring again, this time smashing the floor with his fists and making everyone step back. “The Universe is in trouble! Take me back home! NOW!”

“He’s clearly out of control!” Luna proclaimed with an authoritarian tone she used to have when talking about important topics. “Sister, we must seize him immediately if we want to protect our subjects!”

"I have to agree!” Celestia replied, igniting her horn and unfolding her huge wings. “I’m sorry, Twilight, but I think it is safe to say negotiations are over!”

"No!” Twilight yelled. “Princess Celestia, stop!”

But it was too late. The two alicorn sisters were already in the air, both of them charging a magic spell with their horns. And then, they shot. Not many seconds later, two huge beams made the colossal dinosaur scream in pain for a few minutes, until he finally fell back unconscious, destroying the royal thrones in the process. A green sparkle of light filled the entire room for a brief moment, and when the light finally faded away, to every pony’s surprise, the giant lizard was nowhere to be found. Instead, there was a much smaller creature lying on what was left of the stairs.

"Is….Is he…?” Rarity asked with curiosity.

“He'll be alright” Celestia hurried to respond, looking at the fainted young boy with a frown.

“Oh, my!” Fluttershy gasped, trotting to see what had happened with her own eyes, “The royal thrones! They had been destroyed!”

“It is the least of our matters right now, dearest Fluttershy” Princess Luna said, looking at the destruction their opponent had caused. “Although I do appreciate thou concern”.

“Wait a minute!” Twilight exclaimed amazed while reaching Celestia. “Is that a….A HUMAN?!”

“So it seems” The big white alicorn princess replied to her former student with a sharp tone and a cold glare. Twilight had never seen her mentor with that face before. And for the first time in her whole life, she felt afraid of her.

“A human?” Rainbow Dash asked, raising an eyebrow, “But I thought they were nothing more than an old pony legend! They can’t be real!”

“Dash, there's always a bit of truth 'bout legends” Applejack replied, looking at the blue pegasus with a bit of irritation in her voice, “Nopony knows that better than us”.

“Then what is he doing here?” Pinkie Pie hurried to ask, touching the human’s nose to emphasize what she was saying. "Wait, is it a boy or a girl?"

“I don't know” Celestia sharply replied, making the Element of Laughter to step back. “But I will make him tell it to me , even if it is the last thing I do”.

Extreme Precaution

“So you're saying that he first appeared in front of all of you transformed into some kind of giant dragon?" Spike asked, greatly surprised and terrified at the same time, mounted on top of Applejack’s back. The little baby dragon had lost all the action due to falling asleep during the trip, and Twilight had left him in care of Celestia's guards before entering the Throne room.

"Well, I wouldn't necessarily call it a dragon" a dubious Rarity answered, while trying to keep her pace to Applejack, who, thanks to the strong and toned muscles in her legs, was able to move with an impressive speed, passing from a hallway to another in a matter of seconds and barely sweating. "It was a lizard about the size of a skyscraper, but it did not possess wings on its back like I am aware adult dragons do. Actually, now that I think about it, it didn't even have incendiary breath! ".

"But how do you know that...?" Spike made a brief pause to hang on to Applejack. The farmer pony was trotting with such a pace that he almost fell off from her. Even he knew that hitting the freshly waxed floor at that speed could be lethal. "How do you know that he couldn't spit fire?"

"Because if he could" Applejack replied with a heavy breathing. Spike was able to observe that the element of honesty was finally beginning to run out. "He surely would've turned us into some roasted apples".

“I still don't get it” Spike said, scratching his head with his right forepaw in confusion. “If he's already under custody, why do we have to make a magic force field that surrounds the castle?”

“Ah ain't sure, sugarcube” Applejack said, keeping up the speed. “Princess Luna told us all that humans are so clever and dangerous they can easily break free from almost any place, so we can’t let him escape from the castle if it is true!”

“Ugh! How many more rooms do we have to pass through before reaching the royal dungeon, Applejack?” Rarity suddenly asked, with her mane disheveled and her fur full of sweat. Unlike Applejack’s, her hooves were not made to resist a punishment of that kind, and she was starting to get annoyed. “I highly doubt I can run much longer! I haven't even brought my couch!”

“We're almost there, Rares” the orange mare replied, trotting as fast as she could while ignoring the white unicorn’s protests. Her green, emerald eyes finally spotted a greyish door that did not quite match with the rest of the castle’s architecture. A bat-winged pegasus from Luna’s royal guard who was protecting the entrance with suspicion hurried to open it when he saw the two mares and the dragon going directly to his position. Celestia, who was also there, turned around to receive them. “Aha! There it is!”

After stopping on her tracks abruptly, Applejack hurried to kneel before her majesty. Spike took the chance and let himself fall to the floor, while Rarity fainted like a lady in a Shakespearean play.

“Ground! Sweet, beautiful ground at last!” The purple dragon exclaimed, kissing the floor nonstop.

“First Rarity, and now Spike too? Why does everypony around me over exaggerate everythin'?” Applejack said to herself, letting out a sigh of frustration.

“I'm glad you’ve all managed to come here so fast, Applejack” Celestia said with a warm, honest smile. “I suppose my sister and the others are busy creating the magic field”.

“Yer right, Princess” the farm pony replied, while rising up from the floor. “Pinkie Pie insisted on guardin' the main doors so nopony could interrupt us, 'n Fluttershy decided to stay with her. So, where's that human now exactly?”

“He's down there right now, inside of one of our special cells. I’ve let both Twilight and Rainbow Dash alone so they can interrogate him. I'm sure he'll spill the beans very soon” the big white alicorn replied, pointing out the already open entrance with her left fore hoof and a sharp tone. Her attitude had changed as fast as a dragon ready to protect its treasure.

Applejack raised an eyebrow and squinted her eyes. She could tell something was not right with the princess. Both Twilight and her still remembered that cold glare she had on her face when she saw the human for the first time a few hours ago. Granted, Princess Luna was not the most social pony there was and she could sometimes discuss or announce things with a very solemn, archaic tone-After all, being trapped one thousand years on the moon makes you lose how the world around you evolves-. But this behavior coming from Celestia was rather unusual, if not suspicious. Even though they’d barely interacted all those years despite becoming an Element of Harmony, she was aware of how kind and honest Celestia could be. According to the tales Granny Smith used to tell her and Big Macintosh when they were both foals during those precious summer nights, the Apple family had had a strong and beautiful relationship with her for centuries ever since they arrived to the future land of Ponyville, and they all had described her as polite, pure and noble. Either they had discovered an unknown facet of her personality or Celestia knew something she didn’t want them to know. And if that was the case, she was not doing a very good job trying to hide it, and this was an observation coming from a terrible liar. However, it was neither the place nor the time to make judgements, let alone childish accusations.

“I don't mean to sound like I'm criticizing your royal decisions, princess” Rarity said, finally getting up from the floor. Applejack still couldn’t understand how her friend always had the ability to express herself every time she was having one of her, as she and the others used to call them, “drama queen moments”. “But, don't you think it is a little, uh, what is the nicest way to say it….foolish to put Rainbow Dash to interrogate the prisoner?”

“I am very aware of Rainbow Dash's occasional ruthless attitude, Rarity” Celestia slowly replied, changing neither her posture nor the tone in her voice. “But I'm also certain that Twilight will stop her from doing something inappropriate. After all, that’s why I chose the two of them to lead the interrogatory after all. I've always saw them as two complete opposites”.

“Oh! You mean you're relying on the old Good Pony Bad Pony routine?” Spike asked with curiosity.

“That is correct, Spike” Celestia affirmed. The same smile she had received Applejack and Rarity with returned once she turned to talk to the little dragon. Both the unicorn and the farm pony noticed this sudden change and exchanged a quick glance between them. “I know it's not the most orthodox method, but I know Twilight will be able to pull it off. I believe in her”.

“Maybe we should go down there and see if they need any assistance” Rarity suggested, looking at the terrifying darkness that surrounded the opened dungeon’s entrance. “It might make things easier for them”.

“Are ya sure about that, Rarity?” Applejack asked, scratching her head with her left hoof. “'Cause Ah don't really see how we could be useful”.

“Applejack!” Rarity shouted, genuinely amazed. “How can you ask me such a thing? Of course I am sure! After all, it is our moral obligation to help our friends in need, especially in such a confusing situation as this! It doesn't matter if we are not sure if Twilight and Rainbow Dash are alright without us or not. We must see it for ourselves!”

Applejack blushed and lowered her head embarrassed. Even she couldn’t believe what she had said. An uncomfortable silence surrounded the room for a couple of seconds.

“Yer right!” she finally affirmed, raising her head with determination while adjusting her stetson. “Princess, we’re goin' in there right now!”

“Very well” the princess nodded, stepping away from the door, letting the way clear for the two ponies. “Remember that I will enter immediately if things get out of hoof down there. And whatever you do, do not believe a word that human says. Their species are experts when it comes to lying and manipulation”.

The farm pony and the unicorn exchanged a quick glance once more and then nodded.

“Alright!” Spike exclaimed, raising his fist like a knight ready to save her princess. Rarity giggled, slightly impressed. “Human, here we go!”

“Oh, I'm sorry, Spikey-Wikey” Rarity said, stopping the little dragon on his track with her right hoof. “But I think it will be better for you to stay here with the princess until we’ve dealt with that ruffian. Just in case something happens, as you will understand”.

“What?” Spike asked, frustrated. “But I want to go! I’ve never seen a human before! This isn’t fair! And besides, Twilight needs his number one assistant!”

“I would hear Rarity of I were you, Spike” Celestia said with a frown. “We still don't know how dangerous this human can be, and the last thing I want to think about is losing you at his hands”.

“But, but I…” The purple dragon protested, turning to Applejack, searching for support. “Applejack, please! Back me up, will you?

“Spike, this ain't up for debate” Applejack stated sharply. “Yer staying' here, where it is safe for ya. Period. We don’t want ya to get hurt”.

“Fine” Spike sighed in defeat with a mix of emotions. He felt betrayed and excluded, yet he could still understand their concern. He saw as Rarity and Applejack entered into the chamber and disappearing in the darkness while going down the grey, concrete stairs.

“Good luck” Celestia managed to say. There were no signs of happiness or rage in the alicorn goddess's face now. Instead, just one emotion remained.

Fear.