My Little Pony: Friendship is Magic - Pinkie Pie Evolution Line

You know, I was just going to redo all of them evolving into alicorns, but this was better than I've realized.

Her becoming dark by a trade makes perfect sense. It's like saying I don't really care about so I'm going to get rid of you for something better. Pinkie then become depress because her trainer doesn't love her. And now hate fill her and it makes her evolve.