Derpy, is a grey mare that has 2 different eye's from a different eye view. ( Is also some times called Ditzy Doo, but thats just a rumor. They both look the same, its just hasbro made 2. She is one of the mane background ponies. You'll often see her in the background but, will appear throughout seasons frequently. It appears to be that Dinky Doo, is either the daughter, or sister. We won't really know. Derpy also has a crave for muffins. Many people say she has a crush, on the doctor. We may never know … Watch My Little Pony Friendship Is Magic, on the Hub! We'll, that's all for now! :D