Original Justice League | The Atom
After several failed attempts to tap into the properties of white drawf-star matter, University of Metropolis physics professor Ray Plamer finally succeeded during a cave-in on a school trip; turning the matter on himself, he shrank down to microscopic size and rescued himself and his students. Filling dwarf fragments into a costume, Plamer decided to fight crime as The Atom. Though his enemies often sell him short, the Tiny Titan was among the original Justice League's heaviest hitters. The Atom and most of his teammates were killed in the nuclear explosion, caused by the death of Captain Atom, that destroyed Coast City.
