This is Nyx from the fanfiction Past Sins by ~PenStrokePony . [link] My friend ~linkshade really loves her; Past Sins is what made him a brony. He gave me an awesome Christmas present and I wanted to return the favor so I made Nyx into a Creepy Pony for him. :3
If you've read the fic you'll know that Nightmare Moon's evil materializes itself in a black mass that attacks ponies' brains... This is what I think it would look like if the evil had possessed Nyx while she was still a filly.
MLP:FiM (c) Lauren Faust, Hasbro, etc Past Sins / Nyx (c) ~PenStrokePony this image was made by me for ~linkshade