10 Essential Superman Villains Not Yet Used In The Movies

8. Metallo

Another villain from Superman's Silver Age, but one that's no less deadly, Metallo is just the kind of monster that would amp up the tension of any superhero film, particularly one featuring a character as averse to kryptonite as the Man of Steel.

Another Silver Age terror created by Robert Bernstein and Al Plastino, Metallo is Superman's worst fear come to life: an android powered by the only element that could possibly kill him. He's featured sporadically throughout the character's comics, but in providing a genuinely terrifying threat, Metallo's importance is best made clear.

There've been quite a few Metallos in Superman's history, but perhaps the most successful is the fourth one, the post-Crisis version of John Corben. Fatally injured in a car crash, Corben happens upon Professor Emmett Vale, a paranoid robotics engineer convinced that Superman will hasten the end of the world with an army of Kryptonian soldiers. Vale saves Corben, but at immense cost. Awakening in a new Kryptonite-powered body, Corben (now going by Metallo) kills Vale, before setting out to take on Superman in his new body.

Metallo might not be able to anchor an entire film, but in providing a complex challenge for Superman - one that forces him to think outside of the Kryptonian box - he must be considered for future use.