The Apple Kid is a character from the SNES game, EarthBound. He is described as a fat, dirty slob, but he is actually extremely intelligent and useful to the quest of Ness and his friends.
He first contributes to Ness's quest with the Pencil Eraser, a device able to get pencil-shaped objects out of the way. However, he needs to be given $200 and food as well. Later in the game, he invents the Zombie Paper, which zombies will stick to, helping the situation in Threed.