Duel Ghoul

From Yu-Gi-Oh!

A Duel Ghoul, known as a Duel Zombie in the Japanese version is a person who is stripped of their free will and thoughts. A Duel Ghoul has only one purpose: Dueling. When a Duel Ghoul is defeated in a Duel they will get back up and repeatedly challenge the opponent to a Duel (they never get tired and even a Bio-Band draining their energy doesn't stop them). Once the opponent falls from exhaustion (in the case when Duel Ghouls first appeared, the energy of their opponents was being drained by Bio-Bands, making them exhausted far more quickly) they become a Duel Ghoul themselves. This makes Duel Ghouls nearly impossible to defeat unless their controller is defeated. If that occurs upon a Duel Ghoul's next defeat, they return to normal. It is said in the Japanese version that when a Duel Zombie Duels no energy is taken because they supposedly have no energy left to be taken. People such as Syrus, Chazz, Mrs. Fontaine and Dr. Crowler were turned into duel ghouls.