Rainbow Dash was napping on a cloud.

It was pretty awesome.

The cloud was fluffy and conformed to the contours of her spectacularly muscled back, cradling her just right to completely forget about the worries of the world below.

She needed this nap. She was exhausted after laughing at Twilight so much.

It's not like it was Twilight's fault or anything. Dash knew that. And she knew she was kind of mean about it.

Actually, she felt kind of bad, thinking about it. Kind of really bad.

But still, she thought with a smile, she was dancing like that. It was so uncool! It was the dorkiest, least-coordinated thing she had ever seen. Even the Cutie Mark Crusader's musical performance didn't come close to the sheer levels of awful that was Twilight Sparkle dancing like a mane-iac (oh, woah).

Went and got that dumb song stuck in her head, too, Dash grumbled, tapping a hoof on the cloud in time to the remembered beat.

'I mean, who could blame me for laughing', she thought to herself, 'Could you imagine me dancing like that? Like, in public? It was so far from radical it was almost lametrocious, and that's not a word I use lightly. That is the grade-A hard stuff right there, but that's what it was. Lametrocious.

If anypony ever saw me dancing like that, I'd fly into the Everfree and let myself get eaten by the first thing that wanted to, which would probably be everything since I probably taste awesome too, 'cause my life would officially be over after that. Like the Wonderbolts would let me in after catching me with that kind of coordination. Ha!'

Rainbow's hoof kept tapping to an unheard beat as these thoughts raced through her head. Thoughts always raced through her head, it was sort of her thing.

Like cool. Which that dancing wasn't.

The thought left a smile as her head bobbed against the pillow-soft cloud, drifting off into what was going to be a most excellent nappage.

Applejack bucked at the tree.

Applejack missed.

“Now, just what in the hay just happened there? Bucks? Kicks? How could you just go and plum miss a whole heapin' tree like that?”

Applejack shook her head and just kept shaking it.

“Now, somethin' ain't right here. Let's try this again, fellas, and see if we can't get somethin' for supper already.”

Applejack bucked at the tree again.

This time her hooves connected, but they didn't hit at the same time. They hit with a one, two.

'Three, four', Applejack finished counting off in her head, even as the uneven blow caused her to twist around and fall flat on her face.

“Now, just what in tarnation is goin' on here?”

Rarity made another unseemly gaffe.

As she worked the delicate satin for her latest ensemble through the sewing machine, taking great pains to keep the difficult material straight and level, it had slipped in her hoof again, totally ruining the seam she was so carefully creating.

It was the third such schoolfilly blunder since seeing Twilight's... little performance.

She felt sorry for the girl, truly she did, but she seemed all better now and really there was no need to have that song still stuck in her head, distracting her so.

It was rather frustrating, to put it in such plain terms.

Never before had such a simple matter as having a pop tune stuck in her head caused her to create so many trivial, silly errors, however. Much like the satin before her, it was unseemly.

“There's simply nothing else for it,” Rarity muttered to herself, working quickly to salvage what she could of her error – particularly for such an expensive material, “I shall have to, what is that expression Applejack once expressed... ah! Yes. 'Whistle as I work'.”

Rarity nodded at her fine decision. In fact, her decision seemed so grand, she just could not stop nodding.

She whistled a single bar of whatever came to mind and winced.

“My, my, that was simply atrocious. Did I truly produce that discordant mess? Truly? Rarity, dear, you must – well, first you must stop talking to yourself, you'll seem a madmare – but you must compose yourself if that horrible composition is anything to go by, which surely it is.”

She tried another bar.

Once more the notes that came out didn't follow any scale, chord, key – anything really.

Still, her hoof seemed to be tapping along to the tune, whatever it was.

“Well, Rarity, what has gotten into y- ow!”

Her fine, silver tongue! Prized treasure of her mouth! How could she have allowed herself to have bitten it! Why, she was about as coordinated as Twilight earlier...

Oh.

Oh, dear.

Rarity fled the boutique, pausing only to grab her 'I'd rather not be seen, but still be seen as fabulous' shades and headwrap.

She had to see the other girls. To make sure...

Who first, however? Now, that was a question.

Applejack? No. No, she'd be put off until last – if this was going to turn out how she expected, the farmer would shake mud and sweat and ick off on her like a wet dog. Not entirely her fault, but best avoided.

Celestia only knew where Rainbow Dash would be around now, and whilst Pinkie Pie was close she was also on the way to Applejack's orchard should Rarity double back after involving Fluttershy.

The pegasus had the added ability to fly, well and truly out of range of an errant hoofstrike or bit of filth touching her pristine white coat. Yes, Fluttershy it was then.

Rarity hurried, noting with horrified fascination that her hoofsteps were slightly out of synchronicity, but remained padding the ground with precise rhythm.

Perhaps she shouldn't have laughed at Twilight. It was very unladylike, but Rainbow's own amusement had been dreadfully contagious...

Rarity's eyes widened in horror, in realization; one was indistinguishable from the other. Dear heavens, it was contagious, wasn't it? Not just the laughter, of course, but-

She redoubled her pace to the cottage.

Fortunately the trek through Ponyville proper had been almost entirely uneventful, with nopony truly around at this time of the afternoon. It was just the cusp of sunset, when ponies had headed home for the day but hadn't quite started coming out for the night. Good, the less who were exposed to her dreadful condition the better.

Fluttershy's cottage looked dark. Animals milled around outside, certainly, but not with purpose. Fluttershy almost certainly wasn't here.

Rarity knocked on the door just to be sure.

She recoiled away, though, immediately after, as if the door had burned her terribly. Instead of her customary two-tone knock, what had come out was...

One, two, three, four.

Just what was happening to her? Was she no longer in control of her faculties?

Good heavens, what would happen if it started attacking her thought patterns? Would she speak in rhyme? What would that even sound like?

Oh. Probably like Zecora.

Rarity cheered from her existential crisis at what could potentially eradicate her notion of self might leave her sounding rather fancifully exotic. It seemed a fair trade-off.

Still, that left her wondering where Fluttershy could be... She hadn't answered for the duration that Rarity had been standing on her doorstep after knocking, contemplating what it would be like to erupt on the Canterlot socialite scene with a Zebra tongue. Or how she'd look in vertical stripes, which were apparently quite slimming...

Hrrm. Perhaps dancing non-stop wouldn't be so bad after all, then. At least she was a much more graceful dancer than Twilight, poor dear.

Rarity trotted away from the cottage thoughtfully, less rushed than she had be when she had arrived. Head held high and proud, she made her way back to the next pony on her list, Pinkie Pie.

She did note, though, as she walked the long road from the cottage to the centre of town, that her hips didn't have that same silky sensuality that they usually did. No longer did they sway like wind rippling through velvet curtains, but now they seemed to grind into themselves like a pair of bent eggbeaters.

And, try as she might, she could not convince her tongue to stay in her mouth, which was rather frustrating indeed.

Perhaps if her head would stop bobbing it would be easier...

Still, this was obviously just the first stages of this dreadful curse taking hold. Soon she'd be forced to dance in her wonderfully alluring way, which would be a sight better than this dreadful asymmetric nonsense.

Still nopony around as Rarity made her final approach to the bakery and darkness was just falling, concealing her shame. Excellent.

The bell above the door rang as she walked in, head down, shades lowered meaningfully. Mrs Cake's voice wafted over the counter with the heavy, sticky smell of day-old stale pastries.

“I'm sorry, dear, but we were just closing when – Oh! Rarity, love, are you here to see Pinkie Pie, then?”

“I'm afraid so. I'm sorry I'm not here to take some of these pastries off your hooves.”

“Oh, that's alright. I tend to make too many some mornings just so I have an excuse to sneak a few at the end of the day,” Mrs Cake admitted sheepishly, surreptitiously sneaking a profiterole when she thought Rarity looked away.

“Honestly, with your figure? I find that quite hard to believe,” Rarity smiled warmly, “I don't know where they'd all go.”

Mrs Cake blushed slightly, warmly. “You're far too kind, dear. Pinkie's just upstairs, I'm sure she'd love to see one of her friends.”

With a smile and a slight nod – which rapidly devolved into a rather prolonged series of head sways – Rarity headed for the stairs to Pinkie's room.

She stopped outside, though, when she heard Pinkie Pie singing.

Singing tunefully. It was a rather saccharine number, as sickly sweet as the candies she was so fond of, but it was definitely a rather pretty piece.

Rarity headed back down the stairs. Whatever they had caught from Twilight hadn't affected Pinkie Pie, at least not yet.

“Leaving so soon?”

Rarity spasmed. She was getting worse. “I'm afraid so, Mrs Cake. Give Pinkie my best, please.”

“Well... alright. Are you sure you don't want something for the walk home, Ms. Rarity?”

“I'm sure I don't, though I appreciate the offer.”

“It just looks like you have a bad case of low blood sugar, and it wouldn't do for you to fall faint--”

Rarity practically dove for the door before she could make a further scene of herself.

The road up to Sweet Apple acres was a long one even under the best of circumstances. Tapdancing up the path like a schizophrenic centipede trying to look over both shoulders at once was decidedly not the best of circumstances.

There seemed to be a pile of blue and yellow twitching spasmodically by the gate to the Apple properties, however.

It was here that she managed to find Rainbow Dash and then, rather succinctly, Fluttershy.

“Ah, here you girls are. I've been looking for you for a little while now. I take it you're starting to notice the same thing that I am, yes?”

Rainbow Dash grunted and writhed in response. Fluttershy squeaked and whimpered underneath her. Rarity raised an eyebrow delicately. It would have been an expression of composed surprise had her head not chosen that moment to make a valiant attempt to leap off her neck in several directions.

“What happened here, darlings?”

Rainbow tried to disentangle herself from Fluttershy, but that plan was foiled by an ill-timed bout of 'The Monkey' that ended up with them tangling further, tails knotted together like a bow, only now with Fluttershy on top.

Fluttershy at least had a decent enough vantage point to explain their predicament.

“Well, I noticed that something strange was happening, like to Twilight,” Fluttershy explained in a voice whisper-soft, “so I went to find Rainbow Dash. But she was napping on a cloud.”

Rarity looked up and noticed a distinctly cloudless sky. “I see. Then what happened?”

“Well, I stood underneath it, calling up to her like this. Rainbow! Rainbow, wake up!”

Rarity had to amend the exclamation marks in her head, as her shout was intent only. Truly, she couldn't have woken a breezy if she tried that in its ear.

“Yes. I take it that didn't quite work, darling?”

“How did you know?” Fluttershy asked in genuine surprise.

“If she had simply woken up, well, this calamity wouldn't quite have gotten this far, now, would it? So, what happened next?”

There was another bout in the pony-heap – one that looked vaguely like an ouroborous attempting a conga line with itself – and the two ponies shifted once more, now with Rainbow on top again.

“I kind of busted the cloud wide open when I started jerking like this in my sleep. And sort of fell on her. And we've kind of been stuck like this for a while now.”

Rarity winced. “That couldn’t have been pleasant.”

“Well, Rainbow and I have always been very close friends,” Fluttershy declared from the approximate region of Rainbow's posterior, “But this might be a little much. Uh, no offense, Rainbow.”

“No, I'm totally on the same page as you here, Flutters. You, uh, mind helping us a bit here, Rarity?”

Rarity's horn glowed, as did the two-pony pile. Unfortunately she attempted this on the three beat, and her head jerked wildly on the fourth, ripping the two ponies apart with far more force than she had intended.

Fluttershy seemed fine, merely falling to the ground with a slight cloud of dust from the dirt path puffing up around her. She coughed daintily.

Rainbow Dash, meanwhile, was flung into the branches of a nearby appletree, tumbling out of it sticky and hair matted with various twigs stuck in it.

Before anypony could comment an orange blur raced past them, legs kicking out occasionally.

It stopped a few meters away from them, or at least made a valiant attempt. The twitching orange blur fell flat on its face and swore loudly. A jerk of its head seemed to push it back upright – Rarity's neck twinged in sympathy.

“Applejack?”

“Huh. Got you girls good, too?”

“Indeed it did. Where were you going in such a hurry?”

“Twilight's. Figured she'd fix this and all.”

“I'm not entirely certain she knows how, though I suppose she does seem our last, best hope at this point...”

“Right.”

Dash spat a chunk of apple out, looking at Applejack oddly. “AJ?”

“Yeah?”

“Why did you tie your hat to your head with rope?”

Applejack's head twitched to the same rhythm that seemed to be looping incessantly in Rarity's own head.

“Oh. Right.”

Rarity tutted, getting in as close to Applejack as she could without them risking headbutting each other, or her horn gouging out somepony's eye accidentally.

This required more distance than one would otherwise hope.

“You're going to destroy the brim of your hat like that, Applejack. It wasn't meant to be bent down like that.”

“Well, I ain't got many alternatives.”

“You could not wear the hat.” Rainbow Dash pointed out as she desperately tried to push herself back up using the tree, fighting the constant waggling of her hips.

“No way, no how is that an option. I need all the familiar comforts I can get at a time like this. 'Sides, makes my head feel naked without it.”

“Thank you for that... wonderfully vivid choice of words,” Rarity said with the sincerity of a child receiving boiled spinach, “I suppose, should this become more of a long-term issue, that I could thread a pull-cord for you. It would look far less ludicrous, at least.”

“Well, that ain't going to need ta happen, 'cause Twilight's goin' to fix us up, right good and proper, ain't that right?”

“I certainly admire your positivity. Let's hope it's well-placed.”

“Well, at least it's gotten dark,” Rainbow grunted, “Nopony can see us like this.”

Fluttershy mewled in agreement as her own reasonably rhythmic ball of twitching limbs caught up to the other three.

“I'm sure that's good for more reasons than you know, Rainbow,” Rarity whispered, “As near as I can tell, whatever we have might be contagious.”

“What, Pinkie's like this too?”

“Strangely not. Though I haven't the slightest idea why.”

“Well, consarnit, how do you think it spreads, then?”

“I don't know that, either. Pinkie got the closest of us, yet she's the only one not affected, so it can't simply be proximity to... the infected.”

They had reached the edge of town, now, their clopping of hooves over the cobblestone bridge in declaring their bizarre beat to anypony who cared to listen.

“Pretty sure Twilight didn't bite any of us, so it's not like zombieism.”

“Don't even joke, RD.”

“Who's joking?”

Fluttershy 'eeped' and hid behind her mane, though that was rendered ineffective by the next head toss. She attempted to hide again, jerking her neck out to collect as much of her fringe as possible, but that just rendered the next predictable head-toss that much more volatile.

Didn't stop her from trying though.

“Rainbow Dash, that's no excuse to be crass.”

“No, seriously, think about it. It's not just us dancing. We're dancing like Twilight. She's patient zero! There's always a patient zero in zombie stuff.” Her head bobbed as if to agree with herself, though judging by her scowl it was completely involuntary.

Rarity stopped in her tracks, as much as she could at least.

“Are you saying you don't think this is just the first stage of the disease?”

“I'm afraid it looks that way, sugarcube,” Applejack agreed sadly.

“This is how we're stuck like, then?”

“Eeyup.”

Rarity screamed, shrill and unladylike. “No! No, no, no, no, no, no!”

“Shh!” Rainbow hissed, “You want somepony to see us?”

A few shutters opened. Some ponies leaned out of a nearby club, trying to identify the source of the bloodcurdling cry.

Some snickered. Some chortled. Some giggled or guffawed at what they saw.

Almost all of them laughed in some sort of way.

Rainbow flushed furiously, wincing, head tilting down. “Eugh. Now everypony's gonna see.”

Fluttershy whimpered.

A crowd was starting to form around the edges of the street as they walked. Applejack turned as she 'danced' to face Rainbow, a fierce look of stoic determination etched into her features ruined only by the wrenching jerks of her head.

“Rainbow. Beatbox. Now.”

“What? Why?”

“I have an idea. Just trust me. Beatbox, now.”

Rainbow did as she was told. The group's jerking movements started to match the beat of Rainbow's beat.

“Alright, everypony swallow your pride and get in line. There's strength in numbers and all that. One of us at a time doin' this looks pathetic. We do this altogether, we might come out of this with a shred of dignity. Ante up, everypony.”

Fluttershy whimpered again, but stood flank-to-flank with Applejack. Rainbow fell in on the opposite side.

Rarity sighed, noisily gulping with a too-dry throat, and fell in beside Fluttershy.

Miraculously, together like this, they seemed to reach some sort of coordination with each other. They were still jerking ridiculously, out of their control, but at least now they were matching the pony beside them.

“See? Now it ain't lookin' so bad.”

“Then why, pray tell, are they still laughing at us?”

“Because we still look really ridiculous. Face it, this is just damage control, ain't nothin' goin' to make this look good on anypony.” Applejack's head jerked again, though the rope held fast and her hat remained firmly stuck on her head... sort of. It fell from horizontal to vertical covering her left eye.

“Oh, here, darling, let me help with that—”

Rainbow's eyes widened as Rarity's horn glowed. “No, wait, stop!”

Too late. Applejack was already being hurled hat-first through a nearby plate-glass window. Fortunately the hat protected her from most of the glass damage.

“Ow! Ow, ow! Sugarcube, why'd you go and do a – ow! – gosh darned thing like that?”

“I'm so sorry, Applejack, I was just trying to help!”

Rainbow had stopped beatboxing in shock. The rudimentary teamwork fell apart, limbs falling to their owner's own personal rhythms.

“Right, now we do things my way,” Rainbow declared. She sucked in a deep gulp of air and...

“Everypony, run for it!”

A yellow, orange, white and rainbow blur shot through town to the crystal palace as fast as their horribly uncooperative limbs could conceivably carry them.

“Ah, Twilight? Your friends are here.”

Twilight lay twitching in bed, face down with a pillow wrapped around her head. Her answer was screamed through it, with remarkably less effectiveness than had it been, say, a megaphone. “Tell them to leave, Spike! They're just going to laugh at me again.”

“I don't think they are, Twilight. And, uh, when I said your friends are here, I meant they already sorta let themselves in?”

“What?” Twilight's head jerked off the pillow, and at least eighty percent of the gesture was voluntary. There was a hammering on her bedroom door.

Twilight boogied her way over to it and opened it with a hoof in between bouts of 'The Navigator'.

She was hurled back to the floor by a frantic white-and-purple blob of gyrating motion.

The white and purple blob spoke thus; “Fix this! Fix it now!”

“I know my dancing's bad, girls, but it shouldn't affect you if you don't look at it.” Twilight heaved the words out bitterly,  “I've only abandoned all equine contact for a few hours now, I didn't figure anypony would notice yet.”

Twilight briefly considered the acquisition of a crystal moat, to prevent ponies barging in to her house just to point out her flaws from happening again.

“What? No! Fix us!”

"Us? Why, what's...” Twilight trailed off as she saw Applejack and Fluttershy standing sadly in the doorway, unable to keep their bodies still or, strangely, keep their tongues in their mouths.

Oh. So, apparently, this was happening. Little bits and pieces fell together in her head as she joined the dots.

Twilight glanced around her bedroom. Fragile telescope, fragile and neatly sorted bookshelves, various sculptures she didn't want knocked over...

“Okay, we need to take this to the ballroom, right now.”

There was a clunk and a crack. Twilight jerked her head to look over her shoulder. Rainbow looked back at her – mostly at her – sheepishly, a delicate Fourth City horsehead sculpture in tattered ruins beside her.

Twilight sighed heavily.

As they traversed the castle hallways, Twilight took the time to observe her friends, but otherwise no words were exchanged until they had reached the big, open, no-fragile-objects ballroom. As they entered, nopony dared look up at the ceiling to see what they looked like. Their actions were already being mirrored in their friends around them.

“Alright, sugarcube, so what's the cure? Ancient amulet in the Everfree? Some complicated ritual whatchamjiggit? Rainbow Power?”

“I'm sorry to say this, girls, but I've been looking all day for something, anything, that could reverse the effects even in myself. I had no idea it was contagious until now,” Twilight growled like a truly vicious creature, and everypony reflexively took a boogying step back, “What was supposed to be the 'cure' step on the spell's instructions must have been a trick to try and get the spell to spread mimetically as fast as possible, rather than just risking the spellcaster hide away and keep themselves quarantined.”

“Woah, quarantine. See? Total zombie-”

“Rainbow, you say that word one more time, my hoof is going somewhere Celestia's sun don't shine.”

Rainbow made a mouth-zipping gesture.

“Right, so, just how hard would it be to come up with a cure from scratch?”

“Well, there is one thing I can think of. I can isolate the section of the brain that the spell has targeted and perform an incredibly localized lobotomy that-”

“No.”

“Nope.”

“Darling, please tell me you're joking?”

Fluttershy fainted.

Twilight watched Fluttershy continue to dance herself around on the floor in a circle, in spite of being arguably unconscious. “I'd just have to use a very specific amount of magic that-”

“Rarity just tried to adjust Applejack's hat and ended up throwing her through a building. Her hat. And you want us to let you try doing that to our brains like this. Can you imagine what would happen if-”

Rarity fainted.

“- yeah, see, Rarity gets it.”

Twilight aimed her head directly between the two remaining ponies so that the head sways resulted in her looking between the two of them with some modicum of seriousness.

“Well, that's it, I'm afraid. I don't think there's anything else that can be done.”

“Surely you're not sayin'-”

“Girls... I think we might be stuck like this... forever.”

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