Unsurprising given that it was the home of the Princess of Friendship, Ponyville was quite possibly the friendliest place in Equestria. Usually. Today, however, it was... not. Arguments had burst out everywhere. Hooffights were at an all time high. The police department, with just a pair of overnight cells and a small hooffull of officers, which dealt more in disturbances from the Everfree Forest than civil unrest, were rather overwhelmed. Sad to say, even the Bearers of the Elements of Harmony were not immune, with Applejack, Rarity, and Rainbow Dash themselves being held in separate rooms in the castle, nursing black eyes and bruises from their own hooffight.

Princess Twilight had her hooves full today.

As her unmistakable violet form streaked across the sky, one particular earth pony ran a hoof through is short, messy brown mane. “And there she goes, off to stop another hullabaloo.” A chuckle escaped his lips. “Well, this is all rather horrible, isn't it, Derpy?” he said as he turned to his partner, a gray pegasus with misaligned gold eyes and messy blonde mane.

She nodded. “How did a... what'sitcalled?”

“Nnn'tok.”

“Right, Nnn'tok. How'd one of those get here, anyway, Doctor?”

The Doctor rubbed his chin, with a rather embarrassed grin on his face. “Ahh, well, that may be our fault. Nnn'toks are common pests over at Poleron X, and our little invader may have managed to get into, or even just cling to, the TARDIS on our way home. Watch it!”

The Doctor pulled Derpy into a nearby alley as Berry Punch hit the ground where they were standing just moments ago. “And stay out!” the proprietor of the store she just flew out of yelled just before slamming the door shut.

“Yeah yeah. Like anypony'd want more of your slop,” she grumbled before stumbling off.

“If it's such a common pest, why is it affecting the town so bad?” Derpy whispered.

The Doctor shrugged. “Pests carry diseases. For Poleronians, most diseases are of a psychic sort, and Ponyville would naturally not have any sort of defenses or immunity.” The Doctor pulled his sonic screwdriver from his coat and pressed a button, grinning as the emitter lit up bright green. “Not to worry, this thing's been going for about ten hours now, and should run its course within the next two. Ponyville's a hardy little place, it'll survive. Princess Sparkle will see to that. But we still must find that nnn'tok. Get it back where it belongs. Don't want any other cases like this one, 'specially since we don't know if it's brought any buns in the oven if you know what I mean.”

Derpy nodded. “Oooh. I hadn't even thought of that.” At the Doctor's raised eyebrow she said, “What? Were you expecting me to be all 'Mmmm, buns'? When things're this bad? C'mon.”

The Doctor chuckled as he began making sweeps with his screwdriver. “Of course, of course. No time for silly when Ponyville is punching itself out.” After a moment, he grunted in disappointment. “I can't get a clear reading of the thing,” he said as he shook the sonic screwdriver.

“Try reversing the polarity of the neutron flow!” a high pitched, sugary voice said from above.

The Doctor groaned as he looked up to see a very pink face peering down at the two with a pair of very blue eyes from a nearby rooftop. “Hiya, Pinkie!” Derpy said with a wave.

“Yes, hello, Pinkie Pie,” the Doctor said with considerably less enthusiasm as she dropped from the roof and landed right next to him. “Do you even know what 'reverse the polarity of the neutron flow' means?”

“Nopers! Not a word! But I bet it'll still help ya.”

The Doctor gave a sigh, knowing better than to argue, and punched in the settings. “Huh,” he said, surprised (though even he knew he shouldn't be anymore at this point). “I've got a firm lock on, now. Thank you, Pinkie.”

“No problemo, Doctor,” Pinkie almost sang as she started to skip away. “I gotta go help Twilight with a fracas, now. See ya!”

“She is so weird,” Derpy said with a chuckle as Pinkie skipped away, nonchalantly dodging any hints of violence coming her way.

“Yes, she is,” the Doctor agreed. “Word of advice, never try to figure out the 'why's and wherefores' of that weirdness. That is a road that leads to madness. Now, with my screwdriver set to the right setting, let's...” the Doctor sighed again. It was just one of those days, wasn't it? “It's in the lower levels of the Castle of Friendship.”

Derpy actually laughed at that. “Of course it is. It can't be too easy, can it? So, are we gonna keep hiding in this alley all day or are we gonna go get it?”

“Where did you pick up this near suicidal need to rush into the unknown, Derpy?” the Doctor asked, a small smile on his face as he started back out in the streets.

“From you,” was the response.

“And don't you forget it. Now, come along.”

“You know, you'd think Princess Twilight would have guards or something,” Derpy noted as they rather easily made their way to the basement of Equestria's newest castle.

The Doctor shrugged easily as he continued to follow the path left by their target. Removing his screwdriver from his mouth he said, “That'll come in time. She's rather new to this whole 'princess' thing, and the castle itself is only a couple of months old. Besides, she's left plenty of traps, in the form of enemy-detecting spells and charms. The only reason we're traversing the place so easily is because of that time her future self charmed us against such things. The place already recognizes us as friends, otherwise we'd likely already be caged up at Canterlot, probably with polka-dots in our coats and the taste of purple in our mouths.”

“Like last Tuesday?”

“Essentially, but without the threat of immediate, painful death. We are thinking of the same last Tuesday, aren't we?”

Now it was Derpy's turn to shrug. “Who knows anymore?” she said with a grin. “I'm pretty sure we've seen all the Tuesdays, and we're always caged up under threat of immediate, painful death.”

“True enough,” the Doctor conceded. They continued onward, making light banter until they came to what was obviously one of Twilight's labs, and within it, an odd sight. A large, oval mirror with a gold frame, attached to such an odd arrangement of machinery and devices that it could only have been designed by the Doctor himself, or Twilight Sparkle, and the Doctor was about 86% certain that he didn't make it.

“So, what is it?” Derpy asked.

“Well, it's a mirror, obviously,” the Doctor said, his screwdriver still trained on it.

“Yeah. Duh. But what's up with... the rest of it?”

“No idea, but the nnn'tok's trail ends here.” The Doctor began to hum a little in thought as he put the sonic screwdriver back in one of his pockets. “I do wonder...” he said softly as he gently tried to touch the glass with a forehoof. The hoof went right through, easy as if the glass were water. A mad grin split his face. “Brilliant! It's a portal! The odd patchwork of technology attached to it must keep it self perpetuating!”

“Okay, that makes sense,” Derpy said. “So where does it go?”

The Doctor shot her that smile. The one that let her know she was likely to regret the next few minutes. “Only one way to find out!”

“Oh, no. You're not gonna...?”

The rest of Derpy's question was interrupted as the Doctor shouted “Allons-Y!” and leaped right on through the looking glass, vanishing without a trace.

Derpy brought a hoof to her face. “Oh, this is crazy, even for us.” But when she uncovered her eyes and looked at her reflection where the Doctor had vanished, there was a grin on her face. Really, there was only one thing for it. Derpy took a couple of steps back, then made a running leap of her own.

“Cannonball!”

Derpy's landing was rather on the painful side, it was a hard fall right on her rump, followed by a rolling tumble which left her pretty well face first in the cement she landed on. Eyes jammed closed, she propped herself up on a foreleg and rubbed her sore tush with the other. “Ow ow ow ow ow ow ow ow. Ow. Okay. That was dumb,” she said under her breath. Then her thoughts stopped suddenly. Something... was wrong. It was a general feeling. Her whole body felt off. But there was one thing, one specific thing, that was definitely missing.

“Where's my tail?”

At that realization her eyes popped open, and she brought her foreleg from her still sore back end and into view, and gasped at what she saw. It was considerably more slender than usual, and instead of a hoof, ended in a five fingered hand (and, yes, she did know what a hand was. All of time and space equaled a lot of different species after all.). After a brief moment of staring at the now-wiggling digits, Derpy yelped and leaped to her feet. Or tried to at any rate; her mind and body got into a bit of an argument over whether she was quad or bipedal, and she immediately fell backwards again, right into a pair of waiting arms.

“'Ey. Careful there,” a wonderfully trottingham-accented voice said.

Derpy looked up and grinned. Despite the flat face, small nose, and odd little ears on either side of his head, there was no mistaking those blue eyes, giddy smile, and unkempt mess of brown hair on his head. “Thanks, Doctor.” Then she noticed something and pouted. “You're already walking on two legs, like you've always done it. That's so not fair.”

The Doctor's grin widened. “It's not my fault I've already changed bodies nine times in the past.”

Derpy harrumphed as she struggled up to her feet. She took a few halting steps, her arms stretched out for balance. “And all of 'em were pony-like, so you can't use that as an excuse.”

“Excuse me!” The Doctor said in an affronted tone. “I'm not pony-like, you're Time Charger-like.”

Derpy smirked as she took in the Doctor's full form. Tall and skinny, naturally, and that old brown overcoat of his had changed to fit the new form, with a patch resembling his hourglass cutie mark now sewn on the shoulder of the right sleeve. From what was visible, he was wearing a blue suit underneath, and odd red and white shoes adorned his feet. His posture was annoyingly easy, his hands in his pockets, and his grin was wry.

“I got news for you, Doctor,” Derpy said with a smirk. “It doesn't matter today. You're not pony like or Time Charger-like, today.”

“The same could be said of you,” the Doctor responded.

Derpy looked down and took in her blue top/green skirt combo, with her bubble cutie mark going up the right side of the skirt. “Hey, not baaooaoah!” Derpy came very close to falling over again, but a moment of unsteadiness with her arms wheeling about, and she was able to regain balance. “That is going to take some getting used to,” she said, rubbing the back of her head. She frowned as she noticed something. “Seems like I got a lot more mane than before.”

The Doctor similarly rubbed the back of his head. “Yeah, and yet I seem to have considerably less.” When his fingers found his newfound sideburns he added, “mostly.” His expression brightened as he waggled his fingers in front of his face. “By the way, I love these hands. So very useful.” He withdrew his screwdriver from his coat and began rolling it around his fingers. “Especially for building and operating complex machinery. Can you just imagine how much easier piloting the TARDIS would be with opposable thumbs?” He suddenly dawned a slightly confused frown. “You know, it does make me wonder how we got along with hooves for so long. You know, from an evolutionary standpoint.”

“You can keep 'em,” Derpy said as she slowly turned around and took in the large, rather majestic unicorn statue that they were standing in front of. “I miss my hooves already.” She poked the mirrored base of the statue with a finger and sighed with relief when it rippled as if it was water. “Portal home still works.”

“Excellent,” the Doctor said, his eyebrows doing a quick waggle. “Oooh, I would love to take that mirror home and study her for a night or two. A portal to another world is one thing, especially on a magically strong world like yours. But a portal to another world with such unique morphogenic properties is something else entirely.”

“Getting distracted again, Doctor,” Derpy reminded him, as she began circling the statue.

“Right! Yes! Distracted! Thank you Derpy. Always keeping my head in the game, and my focus on track. That's why I keep you around, after all.”

“And here I thought it was because I was cute as a button and had an adorable, bubbly personality.”

The Doctor coughed, as pink tinged his cheeks and ears. “Er, well, I... ah... wouldn't know about... please, Derpy. It's time to focus.”

Ignoring the smirk he knew was on Derpy's face, the Doctor pointed his screwdriver at the building he just now noticed they were in front of. It was large—far larger than anything in Ponyville, with a design aesthetic that wouldn't have been out of place in Canterlot. It was certainly pretentious enough, in the Doctor's opinion. It was a violet color, with a stained glass window in the center, golden pony heads on each corner, and a clock tower in the middle of the domed roof. It would take hours to search the place for something as small as an Nnn'Tok, even with a precision instrument like the sonic.

So, naturally, it the signal was pointing right at the place.

“Hey, there's a sign here.” Derpy called from the other side of the statue. She ran to a golden horseshoe shaped display not too far away. “Says here the place is 'Canterlot High School.'”

One of the Doctor's eyebrows nearly rose into his hair. “Canterlot 'High School?'” He shook his head with a chuckle. “Alternate universes. Always something juuuust a little different.”

Derpy jogged back to the Doctor's side, even managing to stop without falling flat on her face. “Not gonna lie. I'm not exactly thrilled to be here.”

“No fond recollections of your own alma mater?” the Doctor asked.

“Not really, no,” Derpy said in a tone that caused the Doctor to frown.

“Sorry. I keep forgetting. Why is it I keep forgetting?”

Derpy gave a small but sincere smile. “Don't worry, Doctor. The stuff you forget is usually not important anyway.”

The Doctor grinned. “Quite.”

“You don't suppose it's Saturday, do you?” Immediately after Derpy asked the question a loud, trilling school bell echoed across the grounds.

Once again the Doctor smirked in amusement. “When have we ever been that lucky?”

Author's Notes:

I've unfortunately hit something of a dead end with "Time Keeps Wibbling On." One of those, I mostly know where I want it to go but every time I try to write it nothing comes out" kind of things. So I'm doing something a little lighter and breezier for a bit. Just to keep the juices flowing as it were. Enjoy.