Lord Jabu-Jabu
http://www.rpgamer.com/games/zelda/z5/graphics/screen/z5-023.jpg
This character is a strange one, for all we know about him is that he loves fish. He lives in a nice lake around the back of Zora's Domain. Seemingly, he just sits in one place all the time and does nothing but vegetate and get fat. When inside his belly as a child, slashing him will make him quiver and moan in pain. His belly is the third dungeon in the game.