This story is a sequel to One Boop Mare
Related to the One Boop Mare continuity
Pinkie Pie: The One Boop Mare discovers a parallel reality where a psychotic version of herself seeks to kill all her friends and destroy the world.
The One Boop Mare ain't having any of that.
A silly crossover of my One Boop Mare story line and Smile HD, the awesomely gruesome animation by Dave Davey.