Superman #209 2004

Superman #209, published by DC in August 1968, features the story "The Clark Kent Monster!". In this Silver Age tale, an alien brain-creature engages Superman in battle. After an initial defeat, the creature steals some of the Man of Steel's brain cells and uses them to clone a Clark Kent body, becoming a powerful adversary. This issue is notable for its imaginative Silver Age premise, exploring a unique challenge to Superman's dual identity.