The so-called Iron Eater was an alien monster from an unknown galaxy that emerged from a crashed meteor on the outskirts of Metropolis and went on a rampage through town. He has the amazing ability to shape-shift into anything, which acts a defense mechanism. Eventually Superman locates the creature and takes him to an iron asteroid to let him live out the rest of his days there.
The name of this monster's species is unknown, but it's quite clear that his race is from another galaxy, and they obviously have a strong appetite for iron and steel. They are also barely humanoid, have sharp teeth and fat, orange bodies.