An accident in the lab sends our favorite boy genius to Equestria, as a pony. What will he do and how will he get back? The answer: Science! (Cover Art Updated!)
New FAQ! and TV Tropes!
Planned Phrases from Dexter:
“Pinkie Pie! Don’t push that Button!” /to Pinkie
“Please, Magic is the word simpletons and the ignorant use to describe what they cannot understand.”/ to Twilight
“No, I didn't strap a rocket to you. I strapped you to a rocket.” /to Rainbow Dash
“Friends? Who needs friends?”

Dexter is a boy super-genius with a disdain for anything girlish and no desire for friendship. After an mishap in his lab, he gets stuck in Equestria. How will he cope with the over-friendly ponies, and the girlish everything?
For any who do not know Dexter's Lab: http://en.wikipedia.org/wiki/Dexter's_Laboratory
[RIP Christine Cavanaugh: 8/16/63-12/22/2014] - Dexter's Original Voice Actress

On a dark night filled with even darker magics, an insane cult attempts to give Nightmare Moon a body and life of her own, utterly separate from Princess Luna. But, when the spell is interrupted by Celestia, something unexpected is created.

Now, a little black alicorn filly named Nyx finds herself living under the care of Twilight Sparkle, only to be haunted by memories and emotions from her past. Is she Nightmare Moon reborn or is she simply a doppelganger with a soul and mind of her own? Can Twilight Sparkle protect Nyx from those who refuse to see past her dragon eyes and black coat?

Or, will Nyx be forced to inherit the sins that may not even be hers and become the greatest evil Equestria has ever known?

Twilight Sparkle wakes up one morning to a harsh dose of unreality. She is stranded, without her friends, on an island which matches no known locale on Equestria. Surrounded and harried on all sides by the alien and the dangerous, she will find her mettle sorely tested, and find perhaps that the best friends you will ever have in your life are the ones you make when your back is to the wall...

Thanks to CedricBale and noobie56xx for tracking down the name of the artist so I could give them credit.

Dreams can take strange turns, but lucid dreams are not supposed to. That’s the whole point, to change the dreamworld through lucidity. However, when he tried messing around with his own subconscious, William signed up for far more than he ever thought he was going to.

Now, Reality seems to be following arbitrary rules, cartoon logic and the fact that he cannot change back from his ridiculous alicorn form is just vanilla icing on the bizarre cake.

And unbeknownst to him, a certain Princess is infuriated by the intrusion in her domain.
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That awesome piece of coverart was drawn by the equally awesome mix-up, that you can also find on his dA account here.