Molten Man (The Spectacular Spider-Man)

Mark Allen is Liz Allen's big brother. He eventually becomes an unwilling test subject for Norman Osborn, thus becoming the supervillain Molten Man.

History
In his adolescence, Mark developed a gambling problem. It escalated to the point where Mark steals a car to repay his debts and is sentenced to six months in juvenile hall.

After being released, Mark goes back to school and professes rehabilitation. He is appointed as the operator of the followspot for Mr. Devereaux. During Mary Jane's audition for the school play, Mark takes notice of her and the two exchange glances. Mark becomes smitten with MJ and even doodles a portrait of her during one Criminology lesson.

When Captain George Stacy arranges a Police ride along, Mark is paired up with MJ. The two exchange some ideas on the concept dating, and agree that going out should be more casual and uncompromising. So they arrange a date with no strings attached.

The two then go out for dinner on Valentine's Day, along with Peter, Liz, Harry, and Gwen. At some point, Mark had backslid into gambling. At the restaurant, he spots Blackie Gaxton and goes talk to him. Mark then buys a whole basket of roses to offer the girls. Liz gives him a look, probably realizing he's back to gambling.

When Peter comes back to join the party, after having ditched them to take pictures, Mark blocks his entrance. He states that Liz noticed how he is smitten with Gwen Stacy and that she will not be his second choice.

Mark eventually slides into a losing streak and becomes indebt with Blackie Gaxton. He is dragged in to Big Sky Billiard Room, where he assures Blackie that he will repay him, but Gaxton doesn't trust him. At that point, the Green Goblin barges in their meeting, announcing that he is the new Big Man. The Goblin enlists Gaxton's services, and tells him he needs a test subject. So he convinces Mark that the only way to clear his debt is volunteering to an experiment. Mark is taken to an abandoned police precinct and meets Dr. Miles Warren, who injects him with a solution. Mark becomes alarmed as his skin becomes golden. Dr. Warren tells him he can turn it off with his own mind, but in actuality he switches it on and off with a remove control, so as to trick Mark into believing he could control it. Gaxton declares that they are even, hands him 100 dollars and sends him off to bet.

Mark cannot believe his luck and considers stopping while he is still ahead. However, he goes to the racing tracks anyways and bets on a horse. When Mark loses, he becomes upset and his armor is activated, though it was actually the Green Goblin who did it. Mark tries to switch if off, but to no avail. He goes berserk and makes a run for it, when Spider-Man interferes. He tries to ward Mark off, but he is quickly subdues by Mark's lava powers. Mark heads back to Gaxton and accuses him being deceitful. Then, the Green Goblin confesses that he could never control the armor and they only let him think he did so that he would venture out in public. The Goblin coerces Mark into killing Spider-Man, in return for his normalcy. As the Goblin exits, Spider-Man makes an entrance and Mark takes him on.

Mark tosses the webslinger around, tarnishing the whole place and accidentally setting the Big Sky Billiard Room aflame. When he realizes that Liz and MJ are trapped inside, he tries to help, but his fire powers cause the place to cave in. Spider-Man manages to spring everyone outside, where Li and MJ unsuccessfully try to reason with Mark. He pursues his attack, and Spider-Man tricks him to breaking a fire hydrant, which quells his fire. Then, Mark is webbed between two lamp posts and deluged under the water spout, when suddenly his armor wears off (though it was actually the Green Goblin who deactivated it). The Police eventually arrive and take Mark into custody.

He is incarcerated in Stryker's Island. When Spider-Man is trapped inside the Vault to test it out, the Green Goblin releases Mark and other prison inmates. The Goblin reactivates his armor and incites him to go after Spider-Man. Molten Man is then compelled to oblige and chases after the webslinger along with Rhino, Silverman, the Enforcers, and a robot duplicate of Mysterio. He first shoots lava into the air conducts to flush Spider-Man out. Later on, Spider-Man challenges Molten Man to hit him with a lava ball from a distance. Molten Man unwittingly complies and Spider-Man pulls Mysterio's robot into the ball's trajectory. Molten Man is ultimately trapped in the prison's tranquilizing gas tank room, and gets knocked out along with the other inmates. Later, he is returned to his cell.