Piccolo's original incarnation was introduced as Piccolo Daimao (Piccolo The Great Demon King), the evil counterpart of Earth's god, Kami. Right before his original body was destroyed by Son Goku, Piccolo Daimao reincarnated himself into the form of an egg, which then hatched into his reincarnation named Piccolo Jr. Even though Piccolo by definition is a demon, his actual race is later revealed to be Namekian, which is extraterrestrial.