Jo-Jo Groff

The leader of a gang of criminals who commit a series of spectacular crimes with the aid of a mighty caveman from Krypton, a Stone Age survivor of Superman’s home planet endowed with superhuman powers identical to Superman’s, who awakens to renewed life after arriving on Earth in a state of suspended animation in the heart of a meteor,and whom the criminals dupe into becoming their friend. Batman, Robin, and Superman finally apprehend the villains in June 1959, and the lumbering Super Caveman, hopelessly out of place on an alien planet in an alien era, dies moments afterward from the combined effects of his recent exposure to Kryptonite and the bombardment of cosmic rays he endured during his journey through space (WF No. 102: “The Caveman from Krypton!”).