Ferro Lad of the Legion Of Super Heroes. He was introduced in Adventure Comics # 346 - #347, along with Karate Kid, Princess Projectra and Nemesis Kid. He was created just to die. Very lame!!
That's almost as bad as killing off an old established character..just to generate sales of comic books.
He was killed off in Adventure Comics # 353, only eight issues after he was first introduced.
He was a mutant with the ability to turn his body into a super strong isotope of iron This ability gave him great strength and invulnerability. Apparently, he wasn't invulnerable enough or he'd not have died in the first place.
They brought him back many years later, in the Legion before the current Legion, but, of course, it was not the same.
"I offer you a Vulcan prayer, Mr Suder. May your
death bring you the peace you never found in
life." - Tuvok.
