John Corben was a small-time con man who was fatally injured in a car crash, but thanks to luck, Professor Emmet Vale happened to pass by. Professor Vale was a pioneer in robotics and erroneously believed that Superman was the first in a wave of superpowered Kryptonian invaders after recovering Superman's ship and mistranslating Jor-El's message to his son. Vale transplanted Corben's brain into a robotic alloy body, which was powered by a two-pound chunk of kryptonite, and instructed him to kill Superman. Metallo, now Corben's new moniker, thanked Vale by snapping his neck and killing him. Despite ignoring Vale's commands, Metallo came into conflict with Superman on various occasions, largely due to his continued activities as a petty thug. Metallo later lost his kryptonite heart to Lex Luthor, though backup life support systems allowed him to reactivate himself and escape. He remained a thorn in Superman's side and was powerful enough to cripple the Doom Patrol. Still, the Indian-born hero who called herself Celsius did blow him apart with her thermal powers. Metallo later received a major upgrade via an unholy bargain with the demon Neron. As a result, Metallo could morph his body into any mechanical shape he could imagine (such as turning his hands into guns or "growing" a jet pack from his back) and project his consciousness into any technological or metallic device. He could also grow to a monstrous size.