Dexter's Laboratory
Mandark Astronomonov is Dexter's black-haired arch-nemesis and rival. He is a brilliant scientist and fellow classmate who is always trying to one-up Dexter. He is also a very cruel and sadistic person who enjoys making Dexter's life miserable. Mandark has a large head and a small body, and he wears a red and black outfit. He is voiced by Eddie Deezen.