Keaton

Ocarina of Time
The Keaton's Mask can be obtained in Ocarina of Time as part of a trading quest. It is the first mask obtained from the shop in Hyrule Castle Town, and can be sold to the guard at the far end of Kakariko Village as a gift for his son. Keaton is said to be a popular character.

Majora's Mask
Keaton is a yellow fox with 3 tails that appears in Majora's Mask. To get him to appear, you need Keaton's Mask and to cut some Moving Grass in North Clock Town or along Milk Road. You must have Keaton's Mask on when you cut the grass. Keaton will then appear and ask you some questions about things in Majora's Mask. If you answer them all right, you will get a Piece of Heart. Keaton's characteristics are derived from the mythological Japanese fox creature, kitsune, and its appearance may also be a reference to Pikachu, or Ninetales, both Pokemon characters.

The Minish Cap
In The Minish Cap Keatons appear as enemies.

Quote from The Minish Cap Keaton figurine: "Appears in various areas. This thieving fox preys upon travelers and merchants. He may not be strong, but he will attack very quickly, so be careful."