What the hay is happening? A strange illness has befallen the residents of Ponyville, a fatal one, but it doesn't stay that way for long. The victims soon change into monsters who crave the flesh of other ponies, all the while reassuring their prey that it is all for the best. Soon, Twilight Sparkle is the only one left who is unaffected, and she barricades herself in her home. It seems, however, that even in death, her friends have a knack for singing at the most inopportune times. It's not as if they're asking for much is it? I mean, nopony is going to eat her eyes.

(Marked dark and teen for some gore, nothing over the top though.)

Play this because JoCo is awesome, and it's kinda what this fic is based off of.
http://www.youtube.com/watch?v=v04H7_fFC90