Dragon Ball Z: Supersonic Warriors/Buu

Buu is the creation of the wizard Bibidi who locked Buu away when he became uncontrollable. After the death of Bibidi, his son, Babidi, decided to make it his life's goal to revive Buu. He was successful, but upon his revival, Buu killed Babidi. After becoming friends with Hercule, Buu's evil side expanded and defeated his good side. This serves as his second form (one he himself calls "Super Buu" but usually referred to as "Evil Buu") in the game.