A convicted murderer, Derek Mitchell escapes from jail looking for vengeance on Mortimer Kadaver, but is involved in an accident on the way which turns him into a corrosive man, his entire skin burned with chemical fire which can eat through walls and floors or maim human flesh. His encounter with Kadaver leaves the latter with a handprint burned onto his forehead and leaves Mitchell inert, although he surfaces at least two times after this, possibly with reduced powers.