NOGGLE

[Folklore] The noggle a mischievous creature in the British isles that isn't really a horse. It looks like a little gray horse with a saddle, but if someone gets on, it dashes into the water where it turns into a burning, blue cloud. The Noggle is also a pest if there are mills around, because it keeps the mills wheels from turning. Sticking a long knife into a hole in the wheel should start it turning again.