Clefairy

Clefairy, as some of you know, was very nearly slated to be the mascot of the franchise and Ash Ketchum's partner in crime, a role that was ultimately handed over to the slightly more memorable Pikachu. This isn't to say that Clefairy is without its merits, of course; it's billed as a "fairy," but it resembles neither what we typically expect a fairy to look like or any particular animal. It's like some entirely made-up genus of globular, pinkish mammaloid, and it's by far not the only one in the game, either.