My Little Pony: Friendship is Magic - Image #741,488

This has been mentioned a lot, and will need to be explained a lot.

The one on the right IS an OC. It belongs to a kid with a life-threatening illness. The Make a Wish foundation collaborated with the guys over at DHX and added his character, voiced by him, to the show.

One on the left: an accented that will probably heal in a while.
One on the right: lived with it for most (if not all) his life.