Details are sketchy with the metal thing. He's a mutant too. His power is accelerated healing. Very accelerated. Like hit him in the chest with a chainsaw and expect him to get up and shred your chainsaw. There is a way of bonding adamantium to bones that gets most people dead in the process. His ability made him the perfect guinea pig. And that was before genetic experimenting on people was the the next big thing.
A version of him has been here a couple of times. You might see him pop up again.