Radioactive Skull

Radioactive Skull is the scientist turned supervillain that joins the Terror Cult and becomes an enemy to the superhero vigilante group known as Fabulous Five.

Trivia

 * His name is based on two villains, the first is DC's villain Radioactive Man and Marvel's villain Atomic Skull.
 * Radioactive Skull is based on Spooky Space Kook from Scooby-Doo, Where Are You!.