Twilight returned with some smelling salts, walking and dancing in a very weak imitation of something she must have seen in 'Northside Story', snapping the tips of her wings like Spike would with his claws.

Rarity's eyes fluttered open. "Oh, darling, I was having the most horrible nightmare. We were all forced to dance horribly, with no grace or elegance, without end."

"You wanna break it to her," Applejack murmured to Twilight, "or you want me to do it?"

"She'll figure it out on her own in a second anyway."

Rarity rocked herself back up to her hooves as best as she was able. She stared down at her limbs with numb bemusement as they continued to splay about. "Drat."

"Isn't there some sort of counterspell?" Rainbow practically begged as she was dragged into a particularly poor interpretation of 'The Twist'.

"I'm afraid not," Twilight sighed, emphasizing the 'afraid', "this magic is too complex, I haven't seen anything exactly like it before, or even close enough."

Rarity retreated to a safe distance from her friends as Applejack's hoof splayed out towards her head again. "So why didn't it seem to, well, infect Pinkie Pie?"

"I don't know, Rarity."

Applejack scratched the bottom of her jaw in thought, at least until her hoof spasmed and started slamming up into it to the beat. The clacking of her teeth made a sound not entirely like maracas. "Or Spike?"

"Probably because he's a dragon, not a pony. The spell might have a species boundary."

"So, Pinkie Pie probably isn't actually a pony then?" Rainbow mused.

Applejack grinned. "Called it."

"Pinkie Pie is definitely a pony," Twilight sighed, "at least to a point zero seven percent margin of error. Trust me, that was one of the first possibilities I looked into in my efforts to explain Pinkie Sense. But, no, that would have made too much sense."

"There must be some reason, then," Rarity insisted, tripping over her own hooves and bumping into a wall, "it can't be just random."

Rainbow shook her head – though once she started she couldn't stop. "It's Pinkie Pie, Rarity. Of course it can."

"She didn't laugh," Fluttershy's whispered to herself, head raising slightly, eyes wide. She bit her tongue immediately, realizing she had nearly drawn attention to herself, ducking her head.

"Think, girls, Pinkie Pie could be the key to everything!"

Rarity had resorted to lying on her back at this point, allowing her legs to flail in the air above her uselessly. "She was there with us, that much is certain."

Fluttershy grew more bold. This time she said it with purpose, on purpose. "She didn't laugh. Pinkie Pie didn't laugh."

Nopony heard her. Fluttershy's confidence leaked out of her like a balloon.

Applejack and Rainbow Dash moved to copy Rarity, Applejack lying comfortably on her side – well, when she didn't end up occasionally flopping like a fish out of water for her efforts – and Rainbow attempting to lie on her back. Twilight watched her with a knowing look.

Rainbow's wings snapped, flipping her off the ground and back on her feet.

"Sorry, Dash, it doesn't work with wings. I'm going to have to strap myself down in the examination bed in the lab if I'm going to get any sleep tonight. Or at the very least get Spike to help. I think I have a spare, you might want to sleep over tonight. Or maybe get one of your own, if we can't figure out what Pinkie Pie already has."

"She didn't laugh," Fluttershy insisted.

Rarity heard her, Fluttershy saw with a smile. She was looking up at her thoughtfully. "It's okay, Fluttershy, nopony is laughing at you. We all look like this, you aren't alone."

Well, Rarity sort of heard her. Fluttershy opened her mouth again to correct Rarity, but it looked like Rarity was still talking, so she decided to wait patiently.

"Earlier, this morning, when we were watching Pinkie Pie," Rarity's brow scrunched up in thought, in memory, as one of her rear legs spun her on the floor in slow, lazy circles, "when we were all, well, I'm ashamed to admit it now, laughing at poor Twilight's unfortunate situation, Pinkie Pie was the only one who was reminding us how awful it must be to have been in Twilight's position."

"Oh yes," Twilight spoke through gritted teeth, her molars possibly capable of turning coal to diamonds at that point, "I remember. I am excruciatingly aware of what Pinkie said."

"Well, yes, darling, but think about it. Pinkie Pie was the only pony who didn't laugh."

Twilight paused a moment, brow scrunching up much in the way Rarity's had, like someone had bopped her on the nose unexpectedly. It exploded into a delighted smile, and her jerking 'dance' seemed to brighten considerably.

"You're right! Rarity, you're a genius! So long as nopony laughs at us, the contagion shouldn't spread until we find some way to fix this!"

Fluttershy looked between the pair helplessly. Rarity turned to her, or at least rolled on her side a little until she was facing the pegasus's general direction, and smiled warmly. "Thank you, Fluttershy, for making me think of it."

She was about to protest, but Rarity's smile was so genuine, and Twilight looked so excited... maybe she'd tell them later.

"So, as long as nopony laughed at you on the way over here, we should be fine, right?"

The four of her friends looked at each other with expressions that all seemed to say the same word, just with a different choice of inflection.

Their looks simply said 'Horseapples'.

"Alright, who wants to be the one to tell her?" Applejack sighed.

"What? Tell me what?"

"Well, you started, might as well finish. I ain't tellin' her," Dash insisted. Rarity glared at her, mouthing 'rude', but Dash noted she didn't exactly jump in to Applejack's rescue, either.

Applejack sighed again, looking up at Twilight from her spot on the floor, trying to retain as much dignity as she could while her legs made it look like she was being tazed. "Thing is, Twilight, everypony saw us on the way here. Everypony. And they were all laughin'."

"Yes," Fluttershy echoed, "all of them. It was awful."

Twilight massaged the bridge of her nose with a hoof as she performed a rather jerky approximation of the Can-Can. "Are you telling me that you have already quite possibly infected the entire town?"

"Kinda looks like it, huh?" Rainbow nodded, then kept nodding and nodding and nodding and-

"Dangit all, Apple Bloom let me have it something fierce before I ran into you gals. Big Mac might be alright, and Granny Smith napped through it, bless her heart, but if Apple Bloom runs into her friends like that-"

"Sweetie Belle!"

"Scootaloo!"

Rainbow and Rarity gasped simultaneously.

"Wait, why am I concerned?" Rarity mused, tossing her frazzled mane back with a flick of her head that, astonishingly, seemed intentional, "Sweetie Belle is far too kind and civilized to laugh at her friend's misfortune like that."

"You mean, like you did?" Rainbow pointed out.

"Well, yes, like I did," Rarity deadpanned. "Oh, who am I fooling, she's doomed."

"Girls, I'm trying very hard not to be offended here, but you're not making it easy for me," Twilight tried to look as stern as she could whilst stuck in a fit of the hokey-pokey. "Could you please ease off the 'Twilight's dancing is a fate worse than death' cracks?"

"We said no such thing!" Rarity admonished.

"You have been implyin' it rather heavily as, what's the word, subtext? Yeah, subtext." Applejack smirked.

"Sorry," Fluttershy apologized.

Rainbow snorted at that. "Why are you sorry? You haven't said anything!"

"Oh... sorry."

"I'm going to Zecora's, to see if she knows anything about this," Twilight declared, loudly, bopping her way to the door to the ballroom, "If you need anything, ask Spike. Just... stay in here, where you can't break anything or infect anypony else. If you need to sleep, I'm sure he can organize more restraints or something. Think of it like a really terrible slumber party."

There was a pause as Twilight considered that. "Actually, you tend to break everything at my slumber parties anyway – I'm surprised it was Tirek that finally did in my old treehouse, rather than one of you. So just play Truth or Dare or something until I get back."

Twilight counted out the beats in her head. Two, three, four, one!

She teleported before the others had a chance to protest.

Twilight teleported every count of four, to avoid the risk of an unexpected head movement causing her to teleport, say, into low orbit. Or inside a boulder. Possibly into a parallel universe.

Worst of all, she could teleport inside a boulder in low orbit in a parallel universe, where there was an imminent asteroid strike, and fall to Equestria and explode.

So, she counted patiently and waited. Just in case.

Fortunately she was never in one spot long enough for people to see her... condition, so she didn't risk infecting anypony. It made the trip to Zecora's hut in the Everfree rather uneventful.

Twilight moonwalked the last ten meters to the hut tentatively. There were no lights, no candles lit. Was Zecora here? Was she just asleep? Would it be rude to wake her even if it was an emergency? How was she going to approach this situation?

"Zecora?" she called with a slight tremor in her voice from the door, "are you home?"

Light flickered into being in the hut, casting harsh shadows into the forest floor beside Twilight.

"Twilight Sparkle, is that you? A visit, I say, much overdue."

The door moved to open, but Twilight held it shut with her magic. Then, realizing she was on a one count, and Zecora faced no such time constraints, she reached for a nearby boulder with her magic and dumped it in front of the door.

The door opened with a grunt from the zebra as Twilight released it, only for the unicorn to watch her black-and-white mohawk bob in confusion around the contours of the boulder.

"You seem to have brought a most unexpected gift, though I do not know what to do with it."

"Oh! Ah, sorry, Zecora, but I don't think you're allowed to see me until you promise not to laugh."

"Laugh? At you? Why surely you jest! But I will hold my tongue firm, if that you request."

"Thank you, Zecora, but trust me, it's not for my sake. My friends have already driven me way past the point of caring. This is for your own safety."

"My own safety, well, now my interest is piqued! So away with the boulder and away this mystique!"

Twilight sighed and gripped the boulder to remove it. She had, unfortunately, lost count as she followed the flow of Zecora's couplet.

Where she thought she was on a two she was actually on a three. Which meant she still had the boulder in her grip for the count of four.

The boulder was sent flying over the treetops at a positively alarming velocity, narrowly missing a passing crow.

Zecora stared after it with a rather surprised expression.

Twilight decided to explain whilst the zebra was still watching the – wow, it still hadn’t fallen yet? – boulder rather than her.

"I got cursed pretty bad, and now I need your help, or else everypony in Ponyville is going to be stuck dancing like this tomorrow, and then for the rest of their lives."

Zecora's ear twitched as the boulder finally, finally, hit earth quite a while away. The thump sounded almost like a distant thunderstrike. She turned back to see what Twilight meant.

The zebra put a hoof to her mouth and choked back a snort.

"It's contagious if you laugh at it, apparently," Twilight sighed, and Zecora's hoof jerked into her mouth in surprise, the strangled laugh dying in her throat. "I warned you!" Twilight accused.

"My, oh my, that is quite a curse, and you say that the laughter is what makes it worse?"

"Or at least spread, yes. It's unlike any magic I've ever seen before!"

"So this curse, it makes you dance like a fool? Never before have I seen a pony dance so... 'uncool'." Zecora smiled a little at that, looking at Twilight hopefully. She had been attempting to mix pony colloquialisms into her speech a bit more, recently, and normally Twilight would have been proud of her.

Normally it wouldn't have been at her expense.

"Actually, Zecora, this is how I normally dance. I guess. I ended up cursing myself trying to fix it."

The shaman's – shawoman's? No, no that just sounded awful – eyebrows shot up. "My, my, that does sound quite reckless. Why not try dance lessons, if you felt so feckless?"

"Too late, now," Twilight grumbled.

Zecora 'hmm'd' thoughtfully, trotting around the wildly volatile Twilight Sparkle, who for her part tried to tolerate the inspection like a doctor's visit.

"Normally I would ask to go inside, where there is more light, but I do not wish to see you knock over my possessions this night."

"Yeah, not being able to hold still is becoming a bit of a problem," Twilight agreed. "So what do you think it is?"

"To be honest, purple pony, I haven't a clue, I don't think it is within my power to fix you."

Twilight sighed loudly. "Thanks anyway, Zecora. I didn't think you would, but–"

"Wait! I may not be able to cure this ill, but I might have a potion to keep you still," the zebra nodded, just once, and turned back into her hut, coming back out with a satchel and watching Twilight's dancing carefully. Then, with all the poise of a ballerina, Zecora rose on two hooves and weaved between Twilight's errant hooves, dodging them with a fluid grace that made Twilight seethe with envy. As a hoof made to strike her from behind, Zecora bent backwards over it, forehooves touching the dirt and carrying the rest of her body up and over, like a slinky.

"A dose of this potion should cause neck-down paralysis, for a few hours at least – so don't doubt the truth of this."

Twilight took a moment to recompose herself. It wasn't Zecora's fault she was so good at being Zecora. It's not like she could be anypony else just because Twilight was feeling a little self-conscious.

"Oh! Well at least this might help everypony sleep. Now we don't have to break out the beds with the straps and restraints."

Zecora's eyebrow raised, and a rather amused smile touched her lips. "Twilight Sparkle, I am surprised. Your interests are bolder than I had surmised."

What did... oh! Twilight felt a blush rise to the tips of her ears.

"They're for scientific and medical purposes," Twilight gently corrected, "nothing else!"

The amused smile just grew a little. For a very short, very bitter moment, Twilight hoped it was enough to make Zecora get infected.

Zecora shook her head slightly, still smiling. "Take this potion to your friends, and I hope this curse soon ends."

"Thank you, Zecora," Twilight said, her gratefulness sincere. "Let's hope the curse just wears off in the morning."

A few jumps later with her teleportation, two, three, four, Twilight found herself back in the ballroom of her crystal home.

Her triumphant return was marred, somewhat, by the spectacular sights that greeted her.

Fluttershy seemed to be dangling from a chandelier, lazily buzzing in small circles beneath it as her wings twitched to the beat. Rarity was buried beneath a pile of apple cores with a distended stomach, groaning slightly, her legs still twitching above her like that of a dying ladybug's. One of the incredibly expensive, luxurious curtains appeared to be on fire, with Spike doing his absolute best to put it out with a row of buckets.

Twilight noticed two things about Applejack. The second thing she noticed was that her hat was now modified with a drawstring, as Rarity had promised. The first thing she had noticed was that Applejack was now bright pink. Rainbow Dash, meanwhile, now had a tail that seemed to have been styled like Rarity's.

Applejack and Rainbow Dash looked at each other, at the fire, at the very confused and annoyed Twilight, then back at the fire. Simultaneously, each pointed a hoof at the other.

"She did it!" they shouted in perfect in unison.

A polished crystal ceiling panel crashed to the ground beside her, shattering into dozens of tiny pieces.

Twilight sighed and took some small solace from the thought that she was about to cripple them all from the neck down.

Temporarily, she amended. They were still her friends.

Just as Spike's last bucket toss managed to put out the fire and save about two-thirds of the curtain, the rope holding Fluttershy snapped, sending her tumbling down for a hard landing – since her wings were locked in their attempt to perform The Navigator – softened only by Spike, who had unintentionally gotten between her and the ground.

A bucket skittered across the floor, clanging noisily, until it came to a rest at Rarity's side, who promptly gripped it with two visibly shaking hooves and, head thrust inside it, ejected an impressive volume of applesauce.

Twilight made no effort to suppress a sigh.

They awoke on the ballroom floor, tangled in the tattered remains of the curtain Spike had thrown over them as a blanket the night before, to a chorus of screams.

"Literally everypony in town saw you last night, huh?" Twilight grunted as she sat up, noting with some satisfaction that the potion hadn't quite worn off. Movement was still difficult for her, so instead of dancing, her limbs just twitched a bit, like they would if a physician were testing their reflexes to a four/four beat.

"Must have," Applejack grunted, pulling her newly-modified hat's brim low. "Probably explains the screamin'."

Rarity groaned something like "Never again," and promptly went back to twitching on her side.

Fluttershy, who was at the end furthest from Twilight, stirred, sitting upright. Her ear cocked like a radar dish, scoping out the sounds of the screaming in the distance. Finally, she looked across the bodies of their three other friends and met Twilight's gaze. "Maybe it's time to write a letter to Princess Celestia?"

Twilight whimpered like a kicked puppy. Fluttershy pulled her 'blanket' up to her chin, looking like she'd just accidentally kicked a puppy.

"That's an option? Yeah, we need to do that," Rainbow Dash agreed, wrapping her pillow over her head.

Twilight relented, shoulders slumping. "Alright, this has gotten way out of hoof. Even if Celestia is going to be really, really disappointed in me, and probably never forgive me for this... We can't exactly hide this from her forever..." The light of hope flashed desperately, almost manically, in her eyes. "Unless–"

"Spike!" Rarity cried, "take a letter, before Twilight can finish her train of thought, please?"

Ponyville was not coping well, that morning.

The infection had spread far and fast since the night before. Neighbours mocked neighbours, friends snickered at friends and enemies ruthlessly teased enemies. Foals laughed at parents, parents laughed at grandparents and grandparents laughed at foals, as is the circle of life.

By midday, when their guttered chorus of hopeless screams awoke the six friends in the Crystal Friendship Castle, hardly a soul was left unaffected.

Save, of course, Pinkie Pie.

She didn’t know why the Cakes couldn’t stop doing the Pony Pokie like Twilight. She had asked nicely, but they had said they didn’t know. Well, less said, more panicked and bawled and pleaded to higher powers, but that was just silly and being silly was her job.

Baking was their job, but they weren’t very good at it at the moment. The kitchen was rapidly becoming a total, ginormous disaster area!

The Cakes seemed very sad, even though their dancing made them look really happy and excited, and that made Pinkie worried. The Cakes weren’t sad ponies; sometimes they worried a lot, probably too much, but they were... well, Mrs Cake called it ‘cautiously optimistic’.

So for ‘cautiously optimistic’ ponies to be so sad was a tad bad.

Pinkie tried helping again, grabbing dropped trays before they hit the ground and pouring ingredients so the Cakes didn’t have to.

“Isn’t there anything I can do?”

“Maybe your friend Twilight could – argh! Bi’ mah tungue,” Mr Cake suggested.

Pinkie frowned thoughtfully. “I don’t know how getting Twilight to bite your tongue would help anything, but I could definitely ask! Absolutely positootly!”

Mrs Cake sighed, moving in a wobbly samba with a tray of snickerdoodles on her back. Pinkie grabbed the tray and put it on a counter, before any more could rattle off. Even if she did get to eat the floor cookies ‘cause nopony else wanted them. “What Mr Cake meant, Pinkie, was that maybe you could get the Princess to help us. I’m sure he just bit his tongue trying to say it.”

Mr. Cake nodded sadly, his throbbing tongue hanging limply out of his mouth, except for the occasional wiggle.

Pinkie ducked and dived under the Cake’s flailing limbs as they danced around the kitchen, doing her best to catch the ingredients and pastries being haphazardly dashed and tossed about the room, since they weren’t nearly as good as dodging as she was.

Which was probably good, usually, because that would have made them harder to eat.

Mr Cake’s tongue managed to work its way back into his mouth long enough for him to talk again, right when Pinkie was enforcing the five second rule. “Really, Pinkie, as helpful as you’re being right now, if you could go get your friend Twilight, that’d be really nice right now.” His genuine smile twitched a bit, like they always did when ponies really wanted Pinkie to go do something that wasn’t... well, wherever that smile was.

“Okie dokie lokie,” Pinkie shrugged. “Twilight’s been stuck like that since yesterday, and she seemed to figure out how to fix it then. I’ll go ask her.”

Pinkie Pie bounced out of the kitchen as a rather stunned Mr. Cake managed to work out two more words, “Wait, what?”

But Pinkie was already off on her adventure to solve the conundrum of the dancing bakers!

It wasn’t much better outside.

It looked like all of Ponyville was dancing like Twilight was yesterday, now, only it was happening today to ponies who weren’t Twilight.

Ponies trying to set up their markets stalls, only for a jerk of limbs to send it crashing down on top of them.

Ponies trying to go about their daily business, only to keep bumping into each other, or walls, or bump each other into walls. Or knocking walls over, in one extreme case.

Ponies trying to deliver the mail... actually doing surprisingly well. Pinkie gave the mailmare a sharp salute.

Itchy hoof. Scrunchy nose. Stomach gurgle. Panicked feeling.

That last one wasn’t part of the combo, it was just because of it.

Pinkie wished she had a megaphone. “Everypony, watch out!”

Two ponies pulling a massive delivery of cooking oil came careening around the corner, at least four ponies in length and two in height. The dancing cart-ponies weren’t able to regain control of the lost tanker cart and it rolled, carrying the burly stallions with it, as it crashed against a building. The street was awash in a thick coating of slippery oil.

More ponies tried to rush to help the cart ponies, but just ended up slipping on the oil, landing on their backs. The slippery, oily dancing ponies just couldn’t get up.

More ponies tried to rush to help the ponies who tried to help the cart ponies, but they, too, just slipped on the oil, adding to the growing pony pile up.

Pinkie watched the technicolour mass of writhing limbs helplessly. There’d be no way she could help all these ponies, and now her path to the Princess’s castle was blocked!

There was only one way across.

She wasn’t going to like it but... Okay, that was a lie, it was going to be heaps of fun, but she couldn’t admit that.

“Cannonball!” Pinkie screamed as she took a running leap, stagediving the ponies.

She rode their twitching, dancing limbs, crowd-surfing the upside down ponies.

“Sorry! Sorry! My bad! Just trying to get through! Oh, you have nice muscles! Wee! Sorry, sorry, that was rude of me. Sorry! He he! This is even more fun than I thought it wouldn’t be, I’ll have to do this again sometime when you’re not all dance-sick!”

Pinkie flopped safely on the other side, prancing away from the twitching, writhing mess of groaning and moaning equinity behind her.

Twilight’s castle wasn’t very far away, because it was a very big castle and Ponyville was a very small town. There wasn’t much room for it to be far from anywhere.

There wasn’t a doorbell, so she knocked.

Pinkie bobbed happily on the spot until Spike eventually answered. It took a while, because it was such a big castle, but she couldn’t just go in. Even if the big doors were unlocked, you can’t just do that.

It wasn’t like a public library.

“Hey, hiccup Pinkie!” Spike greeted her, his hiccup curling a wisp of green flame at her that singed her little pink nose. It twitched irritably.  “Sorry, I’ve had -- hiccup! -- the hiccups all morning. Could be worse, though. Not dancing, at least.” Spike eyed Pinkie’s happy bouncing, “Got you too, huh?”

“Oh, no, I was just bored,” Pinkie admitted cheerfully. “The Cakes asked me if Twilight was better, yet? Or knew how to make them better. But if Twilight knew how to make herself better, she’d know how to make the Cakes better, so it’s sort of the same question, right?”

“Ah, yeah.” Spike nodded. “No.”

Hiccup.

“What? It totally is!”

Spike’s expression went tight for a moment, like he was keeping it in neutral whilst his brain came up with a better position to park it in. There was an audible little click as he finally got it, masked by the sound of another hiccup.

“No, I mean, yes it is the same question, but Twilight isn’t any better. The rest of the girls are all paralyzed until further notice, because apparently it was just easier that way.”

“Okie dokie lokie!” Pinkie nodded cheerfully, still bobbing and smiling. If Twilight thought paralysis was the best solution, who was Pinkie to question her judgement?

“It looks like everypony in town might need some Pinkie-Pie-patented cheering up, so this obviously calls for the biggest dance party this town has ever seen! It’s all everypony can do right now anyway, right? Sooo we might as well make the moster-roaster out of it, right?”

Spike hiccupped again. “Right,” he agreed, somewhat cautiously.

“It’s a good thing I made invitations, just in case of just this very emergency,” Pinkie declared triumphantly, pulling an invitation from her mane from the small filing cabinet that resided therein – held on by a small chinstrap the same pink as her fur, all the better to hide it.

Then Spike hiccupped again. The gout of flame licked the corner of the invitation and then fwoomf, it was away in a burst of green smoke.

“Huh. Should have seen that coming,” Spike stared at Pinkie’s now-empty, slightly singed hoof, before adding a rather lamentable, “hiccup!"

“Did you just send Princess Celestia an invitation to my dance party?”

“Err... I guess so?”

“Woo-hoo!” Pinkie cheered, “Now I gotta make sure everypony comes if Princess Celestia is going to be there! Thanks, Spike!”

“Uh... you’re welco-hic!-me?”

“Try a teaspoon of sugar!” Pinkie called over her shoulder, already pronking away, hoofing an invitation to everypony she passed. “I gotta go help some ponies!”

Spike shrugged and turned to go back inside, hiccupping.

“Ugh, puh-leaze, Miss Spit-fi-ah, must you fly through all these deee-sgusting bugs?”

“I’m very sorry, Ms Shores,” Spitfire spat through gritted teeth, “but the Wonderbolts don’t normally act as a taxi service. We aren’t exactly unencumbered with this giant golden chariot you insisted on.”

“Well, whilst I am grateful for your services, Miss Spit-fi-ah, you must understand, I could not just leave my stage behind! These ponies are expecting a performance!”

Spitfire grunted. “Please, Ms Shores, stop dancing in the chariot. You’re throwing our balance out of whack.” Beside her, Soarin twisted uncomfortably in his restraints. “If you don’t stop bouncing around, we’re just going to end up hitting more bug swarms.”

“A pony does not receive an invitation from dragon mail unless the event is most exclusive!” Sapphire Shores declared, bopping and grooving away in her very spacious chariot, sparkling gold and rubies and emeralds and, of course sapphires.

Did you know gold weighs more than even lead? Spitfire and Soarin were becoming increasingly familiar with that little factoid.

“Darnit, Spits,” Soarin’ shout-whispered at the captain, neck-veins bulging slightly, “she’s melted down the entire treasury to make this thing, and I’m not an endurance flyer.”

“She’s paying for it, though,” Spitfire reminded him, “and you know how much that Rarity is charging us for new flightsuits!”

“Oh, man...” Soarin made a whiny little noise, not unlike a kitten with colic, “I really want that. Have you felt the fabric she uses? It’s like a second skin, if skin hugged you back.”

“Besides how obviously gross that mental image is,” Spitfire stuck her tongue out in disgust, getting a bug in it as a reward, “this is what we need to do to get it.”

“Ah! There it is, there it is!” Sapphire Shores cheered behind them, “and look at that, party’s already underway. Hoo-wee, these po-nies like to par-tay! Look at ‘em go!”

Spitfire and Soarin’ looked down. Those ponies certainly were... energetic. They decided not to remark further, though.

Fleetfoot, however, had less tact. Probably because the chariot only had room for two ‘puller’ ponies, and her mouth ran as fast as her laptimes.

“Wow, everypony down there is dancing like a total spaz!”

Sapphire Shores gasped and made some loud, hacking, choking noises which Spitfire took as the universal wordless phrase “I am not leaving a tip”.

“Fleetfoot!” Soarin’ snapped.

“Go ahead and scout for somewhere for us to land right now.”

“Harrumph!” Sapphire said the word as much as she performed it. “Some ponies just don’t appreciate jen-you-wine enthusiasm in this day and age. This is going to be – ah! – fab-u-lous!”

Spitfire shot an aside glance at Soarin’, and noticed him doing the same.

Right.

“Faster, my wonderful entourage, faster!” Sapphire cheered, leaning forward in her chariot, shifting its centre of gravity just enough to seriously panic her two drivers but not quite enough for them to fall out of the air, hurtling to their deaths. The pop-star remained blissfully oblivious, as much of how near she had come to her short-term doom as she was of the doom that awaited her below.

There.

It had taken at least an hour, but Pinkie Pie had delivered an invitation to every single pony in town!

She was getting slow. Maybe it was babysitting for the Cake twins so much... Maybe she was just getting older.

Maybe it was just all the time it took to find the ponies hiding, too embarrassed to be seen in public.

There were a lot of those.

That was probably it.

Well... that left her with a remarkable lack of things to do until the party.

“Hey! Hey, Pinkie Pie!” Applebloom shouted at her.

Wait, why was Applebloom shouting at her?

Oh right. Because the last pony on her list was Cheerilee, so she was still waiting next to the schoolhouse. That made sense. Her route had been the first ponies she saw, then the ponies she found, then the last ponies she’d look for, and then the rest. This route obviously put Cheerilee last, because she had spent a lot of her younger years ‘finding herself’, she said. Pinkie just assumed she’d already be good at getting her own invitation.

She hadn’t. Apparently ponies who practice finding themselves never do anything with it. What a complete waste of time!

Wait.

So why was Applebloom shouting at her?

She plodded happily over to the filly to find out. Applebloom wasn’t alone, though, oh no! There were her two biffle-bestest-buddies, Scootaloo and Sweetie Belle, as well as the two meanie-pants fillies Silver Spoon and Diamond Tiara. Ooh, this looked tense.

They were angrily dancing at each other, in their two groups. Pinkie could tell they were dancing angrily because they were dancing just like everypony else, except they were stomping a lot more and looked real mad.

“Oh, great, why’d you have to drag Pinkie into this?” Scootaloo didn’t moan, because that would have been silly if she had said that.

“Because,” Sweetie definitely replied to the thing Scootaloo didn’t say, “she’s an impartial observer. She’ll settle this once and for all!”

“What’s an imparcel observer?” Applebloom asked, twisting her head from Pinkie’s approach to Sweetie Belle, probably on purpose.

“Am I the only pony who listens to Twilight’s lectures?”

“Yes,” Applebloom and Scootaloo declared simultaneously. Sweetie seemed to deflate a little, or at least dance a little closer to the ground.

“Alright, Pink one,” Diamond Tiara declared to the now-arrived Pinkie Pie, “settle for us once and for all –”

“That’s what I said!”

“– who the better dancers are. I think you’ll find that we have far more grace than those... blank flanks.”

“Alright!” Pinkie agreed, nodding. This would be fun. She plonked herself down on her butt and put on her best appreciative-audience face.

“We’ll go first!” Scootaloo insisted, dancing her way into the center of the makeshift circle. She grooved it out, just like Twilight had, but without any music to help her along. Pinkie started beatboxing, ‘cause it seemed like the right thing to do, really, and Scootaloo gave her a grateful look.

After a few seconds of dancing, Scootaloo moved back to her friends, who patted her on the back supportively. Well, tried. They came really close to it though!

Diamond Tiara went next, and Pinkie Pie dutifully kept up the beat. She was just as bad as Scootaloo was, no better or worse! Just as confident, though.

“Beat that, blank flanks!” she sneered as she fell back to Silver Spoon’s side, the other filly grinning triumphantly.

“We’ve got this in the bag!” the grey filly whispered loud enough for Pinkie to hear.

Sweetie Belle looked nervously at Applebloom, but was sent boogying into the middle with a determined nod of the head with the big red bow.

She danced, never looking at her opponents, occasionally sending a pleading look Pinkie’s way, but she stayed for the entire length of her time, which made Pinkie happy for her.

She couldn’t tell her how proud she was of Sweetie’s bravery, though, because her mouth was too full of beatbox, but it seemed Applebloom and Scootaloo totally had her covered.

“Alright, let’s show these fillies what a real dance master can do,” Silver sneered as she stepped into the showdown ring, locking eyes with Sweetie and holding them as much as she could for her routine, which was kind of exactly like the other girl’s routines, but they didn’t seem to notice that so, who was Pinkie to judge?

Oh, right. She was the judge. Silly her.

“Alright, time to show these two how it’s done down on the farm!” Applebloom shouted triumphantly, jumping in immediately after Diamond’s graceless exit and grooving out for her allotted time. Still looked exactly like the others, but it looked like she had a lot of fun doing it, which was good for her. Then it was over.

“Ah, Pinkie? You can stop beatboxing now.” Applebloom grinned hopefully.

Diamond Tiara pouted, an expression like apple vinegar; possibly sweet, once, but spoiled rotten and turned to acid. “Yeah, tell us we won!”

“No,” Pinkie hummed thoughtfully, a rare sound indeed from her, “I’m pretty sure the Cutie Mark Crusaders won that one.”

“What?!” Diamond Tiara snapped, like a bear trap, “How?”

“Your dancing was mostly the same,” Pinkie admitted, “but there's more of them, isn't there? So they had more of it. If you had more friends, I'm sure it could have been you. But you don't!"

At least she made Applebloom and Scootaloo laugh, but it seemed like the losers would be grumpy for a little while.

That was when the golden chariot pulled by the Wonderbolts flew overhead!

“Woah? Did you girls see that?” Pinkie breathed, neck craned at an impossible angle. “And they’re heading right for the center of town! Come on, let’s go check it out!”

Her head snapped back, since it’s kind of hard to hold the top of your head to the middle of your back just to watch ponies. When it did, she saw Scootaloo already helmeted up, grinning defiantly, dancing excitedly. Well, dancing like she was cursed to, but kind of enthusiastic about it.

“Jump on the cart,” she grinned, “I’ll take you.”

The golden chariot had landed hard, which was great for Sapphire Shores, as it hit the mechanisms with enough force to unspring the chariot into the glorious golden dancefloor stage it could be. Elevated above on a golden podium encrusted with jewels, Sapphire clutched her mic.

Spitfire and Soarin’ did their noblest, most valiant best to climb out from under a gold panel that had landed on top of them, which seemed to involve a lot of wriggling.

“Hell-o, Po-ny-ville!” Sapphire Shores boomed, her incredibly expensive portable stadium sound system amplifying her voice. “Are you ready to dance?”

This got some confused looks from the town’s ponies.

Of course it did. They were obviously ready, just look at ‘em go!

“Here is the latest and greatest that I, the fabulous queen of pony pop have to offer you! Are you ponies ready?”

A crowd was milling.

From the speakers, a dull bass throbbed.

A crowd was being drawn like moths to the flame.

Sapphire smirked as ponies, all of them carrying the same invitations that had led to her own arrival, came to see her stand there fashionably early.

A crowd had become a mob.

It's close to midday... and catchy rhythms got you playin’ your part

So let’s all boog-ay, feel the beat and feel it in your heart

You gotta dance... So tremor at the sound that I’m unleashin’!

So break it down! Feel helpless to the beat it’s so enticin’,

It’s paralyzin’!”

Ponies were all dancing now, in a neat, orderly grid. They seemed just as confused as Sapphire was. Did they plan this? Was a demo leaked? She’d have to call her manager.

They were even all dancing exactly the same. It was exactly like the groove she had in her head. She couldn’t help but join them as she kept singing.

“'Cause this is thriller, thriller right,

Everypony’s gotta dance so come on let’s get you psyched!

You know it's thriller, thriller night

You’re dancing for your life inside a killer, thriller, right?”

The mob kept dancing. There were screams of panic, of fear.

“Stop her! We can’t help it, somepony stop her!”

A rumble of agreement. Sapphire Shores was about to put the microphone down in disgust, get the Wonderbolts out from under her stage and fly her back to Manehattan, where ponies were more grateful!

But, as her head bobbed to the beat, she realized she couldn’t do it. She had to dance.

'Cause this is thriller, thriller right,” she got into the chorus again.

More cries of distress.

Everypony’s gotta dance so come on let’s get you psyched!

Ponies tried rushing the stage, doing so whilst retaining perfect formation. They didn’t advance upon her so much as they encroached. Their movements were perfectly co-ordinated to the beat that not even Sapphire herself could ignore at this point.

You know it's thriller, thriller night

The ponies knocked the microphone out of her hooves, but to no avail. With the absence of the microphone in her ears, she heard what the ponies were chanting underneath the screams and panic.

They were chanting her song back to her.

You’re dancing for your life inside a killer, thriller, right?”

Sapphire fell, her limbs a writhing mess of frantic blobs, grabbing at a towering speaker for balance as she fell, pulling it down beside her, pointing at the castle.

She screamed into the microphone.

Twilight, Rarity, Rainbow Dash, Applejack (now returned to her usual orange hue) and Fluttershy ‘ran’ to the source of the screams.

A panicked crowd greeted them... sort of. Pinkie Pie greeted them more genuinely.

“Pinkie Pie? What are all these ponies doing upside-down?”

“Well they were all stuck dancing, right?” Pinkie explained with a nod, “And they were all mob-like and panicked. So I got Sapphire Shores–”

“Sapphire Shores was here?!”

“–anyway, yeah, Rarity, Sapphire Shores to lead all the ponies dancing towards the oil spill, so we could keep them all in one place.”

“Well, that makes complete sense.” Twilight nodded. Applejack gave her a look, to which Twilight shrugged. “Well, it makes sense by Pinkie Pie’s standards. And it worked!”

Pinkie Pie beamed proudly.

“I’m sorry, darling, I tried to keep this from you,” Rarity admitted. Whereas normally she’d rest an affectionate hoof across Pinkie’s shoulders, she felt attempting to do so would result in Pinkie Pie being sucker punched. Which would be a bad thing. “But it appears doing so now is unavoidable.”

“Princess Celestia’s on her way though,” Rainbow Dash nodded (and kept nodding), “so yeah, that’s cool.”

“Speak of,” Applejack grinned, tightening her hat so its brim held low, pointing at the sky, “looks like that’s her.”

“It seems she’d understand this is urgent, after the Want-It Need-It spell!” Fluttershy whispered loud enough for Twilight to hear. She wished Fluttershy had been just a little quieter, for once.

Celestia's chariot swooped low over the carnage of town. By the time it stopped beside Twilight and her friends, the Princess had seen everything.

All attempts to bow seemed to be misonstrued by the spell as attempts to 'get on the floor', so Celestia was warmly greeted by a five ponies doing 'The Dinosaur' in synchronicity, with Pinkie Pie bowing but, ultimately, deciding The Dinosaur would probably be more fun. Besides, she didn't want to be the odd pony out.

"Twilight? What in Equestria happened here?"

"A book tricked me," was the rather sullen reply.

"Ah, I see." Celestia smiled warmly, stifling a chuckle. "You always were too trusting of the things you read in books. Let's get this mess cleaned up, then, so you can better tell me all about it."

Celestia's horn glowed, as warm and as bright as the purest of sunbeams, and the pony friends shielded their eyes from its brilliance. Magic flowed through them, snaking through the entire town, touching upon every infected pony in its wake. Then, it was over.

They opened their eyes to Celestia's serene, peaceful smile.

Their knees bobbed. Their heads nodded. Their tails shook. Their tongues wiggled.

Celestia's smile faded, then cracked. "That should have worked."

Fluttershy gasped, pointing a trembling hoof at the Princess. It didn't take the others long to work out why.

Celestia's knees had started bobbing. Her tongue was slowly trailing its way out of her mouth.

Celestia... was infected.

"My little ponies, why do I catch you staring at me like that? I'm certain that, together, we will find a way to... to... oh. Oh, dear."

“Why are you infected?” Twilight panicked, her flailing limbs reflecting her shock, “You didn’t laugh! Pinkie didn’t laugh, and she’s fine!”

"Ha ha ha ha!" A rich, deep, baritone voice echoed around them, "Good show. Jolly good show indeed."

"Discord!" Twilight hissed, "Did you do this? I thought I recognized chaos magic!"

Discord strolled from around a corner, decidedly not dancing, with a lawn chair in his claw and a bag of popcorn in his other paw. "I'm rather ashamed to say that this was most definitely not my doing, young Twilight. It does certainly seem like something I would do, I would admit, but I didn't think of it. A pity. This could have been fun, a few thousand years ago."

"But he's reformed now," Fluttershy beamed, sounding rather proud.

"Quite right, my dear friend, quite right," Discord agreed, unfurling his lawnchair and lazily reclining in it, "Which is why I come to offer my assistance in the matter. I'd hate to see my poor little pegasus friend stuck like this for the rest of her life. It'd grow dull and, frankly, I'd grow bored of it after a decade or so. I presume it would take you significantly quicker, yes? To get bored of it, I mean, not to fix it with your assistance. It’s become rather obvious that, unlike myself, you can’t! Isn’t that a hoot? The only reason Pinkie Pie isn’t affected is because of her rather sterling resistance to chaos magic. She does channel an awful lot of it..."

"Get to the point, Discord," Celestia almost snarled, a firm command for the one being she knew she didn't have absolutely authority over.

Discord was decidedly unamused. It seemed he knew it, too. "Alright, well. I suppose you might want to pick a kinder tone with me, Princess, because-" and here Discord burst into another guffaw, silencing himself with another moutful of popcorn, "-you're just as helpless as the rest of your little ponies. I imagine it would be rather hard to fit on the throne if you couldn't stop grooving about like this lot, yes?"

So be kind, Celestia dearheart, it looks like I might be the only way out of this that you have."