Twilight Sparkle broke time when she got her cutie mark. Now Twilight and Sparkle are sisters from another time. Twilight is hailed as the potentially greatest light magician of all time, and already has a reputation as a hero by the time she goes to Ponyville. This isn't her story, not primarily.

Sparkle is an orphan - her dark magic killed her parents. She lives with her brother in Canterlot's industrial sector because they can't afford anything better. She can't leave either. She's a natural dark mage; while Sparkle won't go mad like Sombra, her reputation is hardly any better. Worse, the law doesn't see her as a good pony.

The fact that the dead don't stay dead around her, or that Thorn - Spike's double - is an undead, soul-eating abomination, are other matters altogether.

(Also has some Slice-of-Life, but fimfiction tags won't let me put it with Adventure.)

Has an ask blog to go with it: Ask Sparkle and Thorn.
Also has a TvTropes page: Split Second Tropes.

Featured on EQD.

Cover art by Swirling Line.

During an experiment with new magic. Princess Twilight Sparkle suddenly finds herself in a strange new world and in even stranger company.

Kai is your everyday guy. He wakes up, goes to work and then comes home again, a monotonous routine that is his everyday life. That is until a talking, purple horse appears in his apartment. Well… so much for monotonous routines.

The Princess has a secret or two though, perhaps a new friendship will help her forget some old ones?

You are Anonymous, a human from Earth. One day, you got lost in a forest, and came out on the other side in a strange, colorful world. And who else was waiting for you, but a strange, red-haired man with a large pack and a creepy grin. After being forced into being a salesman, you are thrust into a strange, new world to sell your masks and bring happiness to everyone around you.

However, will you really be able to do this, being the only human in a world filled with colorful cartoon horses? And what's with all of the ponies ignoring him in the first place, and focusing all of their shocked attention on you?

Rated for language and mild sexual themes.

This is a fic based on the Time Loop Files, the format of which was first codified by Innortal on fanfiction.net.
Here's a brief guide.
The basic idea is, one character (the Anchor, usually the main character of a fictional setting) is looping back to the very first moments of their parent series every time either they die or some kind of time limit expires. They of course end up monumentally stir crazy given enough time.
Eventually others start to loop as well.
The reset is not always perfect. Sometimes a loop's history will be different to the "prime" loop, or canonical plot.
"Crossover" or "Fusion" loops also occur, randomly. These can involve the home loopers having a guest, or the anchor for one universe spending time in another, or replacements of one character by another.
Vacation Loops are where the Anchor (or others) decide/s "buck it" and lets off steam by doing whatever comes to mind. There's little or no attempt to maintain the original timeline.

In addition, and particularly more recently, it should be known that this story has a collaborative element to it - people may submit loop ideas or loops, ideally at the Spacebattles thread (a link to the current version of which is on the Trope page), and they may become included.

There's two page image options, thanks to Filraen - the current page image has been edited by the original creator from this work of theirs.. The other one is here:
http://hourglass-vectors.deviantart.com/art/MLP-Loops-466030169

Fanfics collide, and Bucky from The Chase, and Stupid from the Changeling Doll meet up. Instead of using their powers for good, they decide to be a harmless menace to society. Have you considered pulling The Prank?