John Corben is an enemy of Superman. After a terrible accident leaves Corben near death, LutherCorp scientists experiment on Corben. They replace all of his damaged body parts with robotic parts. Corben also receives a new heart that is made out of refined meteor rock (aka Kryptonite).In the end, Corben ends up being more machine than man and calls himself Metallo. Metallo is one of Superman's deadliest enemies. Superman can only be in Metallo's presence while wearing a protective lead suit. The lead shields Superman from the effects of Metallo's kryptonite heart.Metallo was voiced by Malcolm McDowell on the Superman animated series that ran from 1996 - 2000. He was also portrayed in live action by Brian Austin Green on the TV series Smallville .