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

Harry Potter is a lonly child who isn't treated verry kindly by the relatives he is living with. He Wishes for nothing more then a friend, or someone that is willing to be even more to him. Luckily for him, the spirits of the elements of harmony already knew of that a long time ago and set events into motion that will change his destiny forever.

I have read many HP/MLP Crossovers and realized one thing. In all of them Harry either ended up as a unicorn, a pegasus, or a changling, sometimes even as an alicorn, but never as an earth pony or a Thestral. Now, I think it's about time to fix this.

So, my friends and I woke up in this forest none of us recognize, and were scattered by these wooden dog things. Now I gotta find my friends before we get into any more trouble. Now if only I wasn't a foot tall, and can say more than "Eevee"....

This is a random thought that popped into my head one day. I figured I'd get it out now. Still don't quite know where this'll end up, so let's take this adventure together.

Character tags and categories will be added as needed.

Proofread by Zannblade.

Have any theories? Can't remember who is who? Fear not! Thanks to Adenbadens for starting up a Google docs to help with this. You can veiw it here. Beware, wild unmarked spoilers abound in the grass.