Twilight Sparkle, a little Unicorn filly more curious than a cat, wanders to the top of a mountain to get away from everything and explore. She finds a hole in the mountain, and falls down into it. She expected to die, or to be trapped forever. She set out into the darkness, looking for and calling out for a way home...
...and adventure came.

A crossover of MLP: FiM and Undertale. The latter belongs to Toby Fox, the former belongs to Hasbro and Lauren Faust.
Inspired by The Moon in the Dark, by Tatsurou; please go show him some support.
Rated T for safety's sake; will eventually involve bad puns, minor-to-mild language, possibly moments of violence and occasional crude humor. Oh, and puns. Lots and lots of puns.

Due for revision and revamp.

When you make a mistake, it hurts. When you try to apologize, it can hurt even more. When Gabby Gums made a mistake, she–or, rather, they–ran from it. This is what followed. AU "Ponyville Confidential" ending.

When the Cutie Mark Crusaders realized the error of their ways in the Gabby Gums incident, they made it clear to Ponyville how sorry they all were. An apology letter was printed for the final Gabby Gums article, apologies were made, and punishment dealt towards the blackmailing Diamond Tiara.

But what if it didn't happen that way?

Overwhelmed by guilt and convinced that the town they call home doesn't want them anymore, Apple Bloom, Sweetie Belle and Scootaloo submit their apology letter and bid the town a sad farewell, vanishing from the streets without any further comment. Shocked and consumed by guilt, their friends and families start a mad search to find the little fillies and bring them home. Meanwhile, in the Everfree Forest, the Crusaders themselves find that running away is much more painful–and dangerous–than they had expected.

Idea given by Waspinator331, written by request. Please show him some support.

Miles "Tails" Prower has been through a lot in his life. He's grown up from being the spunky, two-tailed sidekick to Sonic the Hedgehog. While he still loves his "big bro" and loves to spend time with his friends, life hasn't been entirely kind to him, and has left him with scars.
But now, a desperate situation has caused him to botch an attempt at Chaos Control, sending himself across dimension to the land of Equestria. Recovering from a battle, stranded in a town full of ponies who use magic as a part of every day life, and surrounded by an assortment of personalities who all see him as being as much a curiosity to them as their magic is to him, how will he cope? Will he find new friends? Will he find his way back to his own world?

This story is an alternate sequel to "Nightmare Moon's Tiny Adversary", and "Celestia's Tiny Student", by CommanderX5, written with their permission. I recommend reading them, though it may or may not be "needed", per se, to understand this fic.
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After the defeat of Nightmare Moon and the return of Princess Luna, Twilight Sparkle has decided to stay in Ponyville to live in the Golden Oaks Library so as to be close to her friends. Tasked with studying the magic of Earth Ponies, she will let nothing stop her from succeeding in her task. With her dragon assistant, Spike, her faithful bodyguards, Overwatch and Steel Blade, and her new Ponyville friends by her side, she's ready to take on whatever challenges her new home may have to throw at her. How will these adventures impact Ponyville and its newest resident when said mare is one one-hundredth of her natural size?
Only time will tell.