A species of ghost foxes, found in Nintendo games Zelda 64: Ocarina of Time and Majora's Mask.
The Keatons are yellow and have three black-tipped tails, which they wag constantly (Miyamoto probably got some ideas from some other N64 games... =) There's no known place to see them in Ocarina of Time, but there are a couple of places to find them in Majora's Mask. The Keatons are pretty smart, and want to know answers to tricky questions - and for good answers, they reward the player.
Apparently kids love the Keatons, so both games include Keaton masks - they're getting less popular in time of Majora's Mask, though... In Ocarina of Time, a guard wants you to get one of those masks for his son.