Midnight Sparkle

Midnight Sparkle, Nightmare is Magic is a unique unicorn that can be found in Whimsyshire and Whimsydale in Diablo III. She has Desecrator and Nightmarish affixes.

Trivia

 * The name and title of this unicorn are a likely reference to Twilight Sparkle, a character from My Little Pony: Friendship is Magic. The Equestria Girls spinoff has "Midnight Sparkle" as the alter-ego of the human version of Twilight.