Planet Master was an enemy of Batman with powers that resembled attributes of each of the planets in the Solar System. He was a mild-mannered scientist exposed to a gas that also gave him amnesia. Once the effects of the gas wore off, he forgot about his villainous exploits. His former lab assistant Edward Burke replicated the accident and became the second Planet Master.
Planet Master was created by Bill Finger and Jim Mooney, first appearing in Detective Comics #296 (1961).