Sir Finkleberg was a knight in shining gold armor during the Middle Ages who was believed to be the hero who would pluck the sword in the stone from its prison, but sadly he failed due to his arm hurting at the last moment. Nevertheless, he still won the sword in the stone home game as a consolation prize. Finkleberg tried to play the game, but when he pulled the toy sword, he hurt his hand. Later he followed Timmy who pulled the sword from the stone when the latter goes to stop the dragon from eating his parents. His sprained arm keeps hurting during the quest, and this strain eventually caused his arm to fall off and get eaten by the hungry peasants.
According to the end of the book Timmy was reading, Sir Finkleberg with his one arm became the world's first slot machine.