FMTM fully rewritten on December 12th, 2019.
Old version backup
Big Mac is also in this story.
Part 2:From man to mare: chaotic convergence
Part 3:From man to mare: an aching heart
Part 4:From man to mare: I love my mommy
Part 5:From man to mare: Time to tell

Derry Wilhall; a man having received a large inheritance from his grandfather, decides to live like he's always dreamed: alone and separated from society. A little excursion through the woods for some sight seeing throws him into the throngs of another world. "He" ends up in a body that is not his and will see things from another perspective.

While experimenting, Twilight's new teleportation spell goes awry, sending her careening into a different world, just in time to take part in a fantastic ritual called Heaven's Feel. Twilight must adapt to the world of humans and take part in the vicious conflict that is the 4th Holy Grail War as a Servant alongside her equally reluctant Master. The duo must contend with powerful adversaries and survive the subtle machinations of the Magi determined to win the Grail at any cost. Can Twilight overcome her unwillingness to take the lives of others? More importantly, should she? And is there any way for the displaced Unicorn to return home? Trapped, alone and in a different world and surrounded by enemies on all sides, does the Magic of Friendship still hold any hope for Twilight?

A crossover with Fate/Zero.

Officially complete!

Trouble is brewing in Equestria, and Spider-Man is summoned to save the day! However, he takes the form of a pony upon his arrival and slowly starts to lose his powers. Now as Peter Pony Parker, he must become Equestria's new hero as the Amazing Spider-Mane, but with past failures haunting his mind, will somepony be able to give him the happiness he deserves and save him from a prophecy that ends with his death?

Across Equestria and through Earth, two hearts will join together, but one may die to ensure the survival of reality...

Cover image drawn by jmkplover and colored by Saljian

Official Theme Song done by XAVI- Playful Banter

It even has a Tvtropes page!

Spiders and Magic: Rise of Spider-Mane

NOTICE: This is an unofficial and highly expanded story adaptation of the "PWaaMLPfim" Youtube Video Series: Phoenix Wright / My Little Pony FIM - Turnabout Storm! The videos came first, NOT this story!!!!

A quiet summer night in Ponyville takes a violent turn when two pegasus ponies enter the Everfree Forest and only one comes out alive, leaving the second accused of murder, on trial for her life. Ace Attorney Phoenix Wright finds himself dragged from his own world, magically summoned to Equestria by Twilight Sparkle to defend Rainbow Dash from charges of killing Ace Swift, a superstar pegasus athlete and champion racer.

Trapped in an unfamiliar world ruled by magical talking ponies, Phoenix must draw on all his wits and experience to solve the crime and uncover the conspiracy behind it... before Rainbow Dash is banished to the sun for a murder she didn't commit.

Parts 1-43 written by RavenRegios, and edited by Firesight. Parts 38, 42, and 44-epilogue written by Firesight with additional input and prereads from TheGoldCrow, AJ_Aficionado, and Leo Archon.

Ownership transferred to Firesight on 1/15/2018.

There is a world where Life and Death govern all imaginable realms. A world where Watchers guard over their planets and the creatures that roam them. In this world, a young soul goes on a journey to a place he never thought existed, after cutting an untold deal with Death.

Equestria, a place of magical creatures and mysteries, offers him a new chance at life. A chance he will have to pay dearly for. This is the written story of his adventures, some of the sorrows and victories of his life as he goes through great challenges and fights his inner darkness.

At the end of this journey, one begs the question: What is better? To be born good, or to overcome your evil side through great effort and sacrifice?

Tagged with Human for the prologue.

Follows show's cannon up until end of Season 2.

Now a published book!
And it's own TvTopes page!

Spanish translation: Here

First chapter published January 2012
Marked as Complete on 31st August 2014
Published (printed) on 25th November 2014

PM me for the full digital version of the now-printed book! (includes text PDF, full cover and fan art)

When your life is as dull a gray as the world that surrounds you, the mundanities can make it all seem meaningless. Sometimes all we need is a little color -- or six -- to reintroduce us to what truly makes life worth living.

*6-16-2017 Edit, added Rainbow Dash tag because it triggered knighty.*