This is a shot from WonderCon of a dog cosplaying as Rainbow Dash from My Little Pony: Friendship Is Magic. Probably not by choice mind you. I'm not sure what kind of dog that was before the whole shaving and transformation, but I'm guessing one that still had some dignity. You didn't even use a girl dog, I can see his penis.
Thanks to laurie, who informed me she wants a Rainbow Dash dog of her own. Well I vote stick to cats.