Another morning in Ponyville greeted Twilight Sparkle as she opened her eyes from a good night’s sleep. The birds chirped outside, and the trees rustled in the light breeze. Twilight rubbed the sleep out of her eyes, and groaned as she got out of bed. She looked to her side to see Spike still asleep. She just shook her head. That dragon loved his sleep.
With half-awake legs, she hobbled her way out of her bedroom and over to the bathroom to tidy herself up. She fought to open her eyes all the way, but her heavy eyelids were making it difficult. Nevertheless, she found the bathroom door and walked inside.
For some reason, it felt like there was a bug on Twilight’s upper lip. She shook her head to scare it off, but it didn’t work. Fortunately for the bug, Twilight was too tired to care right now. Surely when she washed her face it would be scared away.
She entered the bathroom, and turned on the sink. Using her magic, she levitated several globules of water to her face. The cool rush of the water was enough to jolt Twilight awake… somewhat. She levitated a towel over to dry her face off. As she rubbed her face, the towel got caught on something on her muzzle. It was clinging to her face, pulling on the skin as if it was part of her.
Her curiosity ripped the towel away from her face so she could look in the mirror, and if she wasn’t awake before, she definitely was after seeing what was on her face.
Right on her upper lip was a big, goofy black moustache.
A loud yelp came from Twilight’s mouth upon seeing her new facial hair. She immediately tried using her magic to pull the moustache off, but it was firmly on her face. It pulled on her skin, refusing to let go. Eventually, it got too painful, and she released it, smacking her in the face like a slingshot.
“Twilight?” a familiar voice said from outside the bathroom, accompanied by a knock on the door.
“Spike?” Twilight said.
“Are you okay in there?” Spike asked.
“I have a moustache!” Twilight bellowed.
“Um… what?” Spike said.
Twilight swung the bathroom door open and looked Spike dead in the eye.
“Look!” she said, pointing to her new facial hair.
Spike’s expression slowly morphed from scared to one of utter hilarity. A chuckle immediately spawned full-out laughter, causing Spike to fall back on the floor, holding his belly as he bellowed laughter.
“Oh my gosh! What happened?!” Spike managed to say through his snickering.
Twilight was about to scold Spike for not taking this seriously, but stifled a laugh herself when she noticed something new about Spike.
“Um… Spike?” Twilight said.
“What?” Spike said, trying to calm himself down.
Twilight said nothing, but picked Spike up with her magic, and levitated him in front of the mirror…
“Twilight, you know I don’t like it when you—” His expression turned to one of shock when he saw himself in the mirror.
“What the…? I have a moustache too!” he yelled.
“Not so funny now, is it?” Twilight said, putting Spike down.
Spike tried pulling the moustache off, but much like Twilight’s, it was stuck on his muzzle.
“What happened?!” Spike yelled. “What’s going on? Why do we have moustaches?!”
“I don’t know,” Twilight said. “Even more confusing, why do our moustaches look exactly the same?”
“I don’t know!” Spike screamed.
“Stop yelling!” Twilight shouted.
“I’m not yelling!!!” Spike bellowed.
“Yes you were!!!” Twilight hollered.
Before their yelling contest continued, they heard the loud bass of the castle doors opening echo throughout the palace.
“Twilight!!!” a voice called out, accompanied by the sound of galloping.
“Is that Rarity?” Spike said.
Without another word, Twilight raced down to the lower level to see Rarity racing into the main hall.
“Rarity? What’s wrong?” Twilight beckoned.
Rarity refused to look at anyone, being her usual dramatic self. She laid out on the Cutie Map with her leg over her head in her “woe is me” pose. She sounded completely distressed.
“Of all the worst things that could happen, this is THE. WORST. POSSIBLE. THING!” she proclaimed.
Twilight suddenly realized she raced down here with her new moustache. She used her wing to cover her muzzle, and Spike attempted to conceal his with his hands.
“Rarity, just tell me what’s wro—” Twilight stopped when she noticed something on the white mare. “Um… Rarity… are you wearing a bandana?”
“Oh, Twilight,” Rarity cried, “I couldn’t bear to leave the house looking like… OH, IT’S JUST AWFUL!”
Rarity finally opened her eyes and looked at Twilight and Spike. She raised an eyebrow when she saw both of them covering their muzzled.
“Um… why are you two—”
“No reason!” Spike said suddenly.
“Wait a minute… oh goodness, no! It happened to you as well… didn’t it?!” Rarity belted.
“What happened to us?” Twilight asked.
Rarity was silent for a moment, looking like she was about to cry. With a whimper, she ripped her bandana off like a bandage, revealing another goofy, black moustache on her upper lip.
Twilight and Spike gasped.
“You too?!” Spike said.
“I woke up with it, and it won’t come off! I tried everything. Pulling it off… snipping it off… everything!” Rarity cried.
“You’re not alone,” Twilight said, moving her wing away to reveal her own goofy moustache, virtually identical to Rarity’s.
Rarity’s eyes went wide, but her emotional wave seemed to subside when she realized she wasn’t the only one with something unwelcome stuck on her muzzle.
“Well now I’m just confused,” Rarity said.
“Aren’t we all…” Twilight said.
“Twilight?!” another voice said at the entrance of the castle.
In a matter of seconds, in came Applejack, Rainbow Dash, and Fluttershy. Fluttershy was riding on Rainbow’s back with her wings firmly over her face.
And on Applejack and Rainbow’s faces were moustaches. The exact same ones as everyone else.
“You girls too?!” Twilight said.
“Ah was about ta say the same thing,” Applejack said.
“What is going on?!” Spike said, trying to pull his moustache off again.
Twilight noticed Fluttershy curled up on Rainbow’s back with her wings over her face.
Rainbow shook her head. “It was work trying to get Flutters out of her house today.”
“I-I don’t want anypony to see me,” Fluttershy cooed. “N-Not like this…”
“Sugarcube, it’s fine,” Applejack said.
“Yeah, Flutters,” Rainbow said. “They all have the same problem.”
Fluttershy slowly moved her wing to peek out. Twilight looked, and saw yet another moustache planted on the yellow mare’s muzzle.
“Oh…” Fluttershy cooed, slowly getting off Rainbow’s back. “S-Sorry…”
“We’re all just as confused as you are, Fluttershy,” Twilight said.
“And it’s not just us,” Rainbow said.
“What?” Twilight beckoned.
“Come with me,” Rainbow said.
Twilight followed Rainbow to the entrance. They opened the doors so Twilight could get a good look at her kingdom. To her shock, everypony in Ponyville had a moustache, exactly the same as the ones she and her friends had. And they all looked just as perplexed as she was.
“And when we were at Fluttershy’s house, even her animals had moustaches,” Rainbow said.
“What in Celestia’s name is happening?!” Twilight belted, racing back inside.
“What the hay is goin’ on?” Applejack asked.
“I don’t know!” Twilight screamed.
Suddenly, Spike burped a cloud of fire, and in its wake, a scroll appeared.
“Oh good,” Twilight said. “Something from the princess will take my mind off this.” Twilight opened the scroll with her magic and levitated it in front of her.
Dear Twilight,
The weirdest thing has happened. For some reason, everypony in Canterlot has a moustache. The exact same moustache at that. I have one, Princess Luna has one, all my guards have one, everypony. It was kind of funny at first, but this is ridiculous! Do you have any idea what might be going on? I’ve never seen anything like this.
Princess Celestia
“Ugh!” Twilight grunted, throwing the letter off to the side. “This is not how I wanted to start my day!” For the sake of her sanity, she took a few deep breaths, calming her systems.
“Um… Twilight? Are you okay?” Fluttershy asked.
Twilight took a deep breath and turned to her friends.
“I’m fine. I’m fine,” Twilight said. “Now… let’s try to figure this out.” She walked to the library, and heard everyone cantering after her.
“Start looking around. Try thinking of causes for this,” Twilight said. “Quickly! The fate of Equestria depends on it!”
Twilight began pulling all her books on strange magic, puzzling epidemics, and pony biology. She tossed them behind her, and her friends took their pick.
“Maybe it’s poison joke in the air!” Applejack said.
“No, then I wouldn’t be able to fly,” Rainbow said, hovering cleanly in the air with a book.
“And my mane would look horrible,” Rarity said.
Applejack sighed, returning her attention to the book in her hooves.
“Discord!” Rainbow said.
“What?” everyone else said.
“What if Discord did this?” Rainbow said.
Suddenly, there was a knock on the window outside. Twilight flew over to see who it was, and to her surprise, as if summoned…
“Discord?” Twilight asked.
In the blink of an eye, the ruler of chaos himself teleported inside the library.
“Isn’t it a lovely morning?” Discord said.
“What are you doing here?” Rainbow asked.
“Oh… I see the same thing happened to the Friendship Council as well,” Discord said.
“Huh?” Rainbow said.
Discord pointed to his muzzle, making his goofy, black moustache more obvious.
“You gave yourself a moustache as well?” Rainbow said. “Very funny.”
“Oh, you think this was… me?” Discord said, feigning hurt feelings.
“This just screams Discord,” Applejack said.
“Well, I can see your logic, but I’m afraid you’re mistaken,” Discord said.
“Would you mind elaborating?” Rarity asked.
“It was the strangest thing. I woke up this morning, and whaddya know… I have this!” Discord said, pointing to his moustache. “At first I was laughing, but then I realized it wasn’t my doing. I’m the ruler of chaos. Pranks are my job.”
“You think this is a prank?” Twilight asked.
“Only a guess,” Discord said.
“And why should we believe you?” Rainbow asked.
“I understand you still aren’t that fond of me, but I do have an alibi,” Discord said. “Isn’t that right, Fluttershy?”
Fluttershy smiled and nodded. “Yep! We were having tea last night. It couldn’t have been him.”
Rainbow groaned. “Alright, I guess you’re off the hook.”
“See? It’s not always me,” Discord said, feigning hurt feelings again. “But y’know, I do look quite nice with this new moustache.” He materialized a small mirror in front of himself, and acted like he was fixing his hair. “Now, I’m afraid I must get going. When you find the prankster, please send them my way. I’d like to know how they did this. But until then… Auf Wiedersehen.” And just as mysteriously as he appeared, he disappeared in the blink of an eye.
Twilight grunted to herself. “And here I thought this was a weird disease epidemic. I never even considered that it might be a prank. Ugh… this whole thing has been messing with my head.”
“Um… speaking of which… I just realized something,” Spike said.
“What’s that?” Fluttershy asked.
“Where’s Pinkie Pie?”
MEANWHILE
A familiar pink mare trotted her way through the Crystal Empire. She carried two saddlebags, filled to the brim with… items.
“Almost ready,” Pinkie Pie said. “Now… I wonder if they sell super glue here…”
With a loud guffaw, she bounced her way through the streets, giggling to herself. Pranks are so much fun!
Author's Note
Y'know, I have a feeling somepony in Ponyville would've figured out what was really happening a lot sooner than they did, but for the sake of comedy, I made them all… well… very melodramatic. I wanted to go with total melodrama with this, and I hope I somewhat succeeded? 
I uploaded this completely unedited. I finished it, and immediately uploaded it. I'll reread it later for mistakes, but I just want to see how I did. So what you just read was completely raw. Hopefully it wasn't too much of a mess.
This was a random idea I had when I looked at a picture of Pinkie Pie with a moustache. Again, written completely impromptu. Hope it was alright, and not totally cringe-worthy.
Thanks for reading! 
