Molten Man was a prominent villain of Spider-Man.
He was shown causing havoc on the waterfront where he was robbing some gold until he fights Spider-Man and Triton. Molten Man's heat gives Triton a disadvantage until Spider-Man helps him. Spider-Man then pursues Molten Man into the streets and into a construction site where he uses cement to help defeat Molten Man.
Later Molten Man became a participant in the Contest of Champions -- a game between the Grandmaster and the Collector, where he, Kraven the Hunter and the Wendigo King battle against Spider-Man, Iron Man and Hulk. After Iron Man and the Hulk are taken out of the game Spidey battled them on his own. He tricked Molten Man onto the docks were he burned through the wood into the lake. He was returned to his stasis pod.