Amazing Spider-Man#133(1974)

The Molten Man has come after Ned Leeds, who has been taken to the hospital by Peter Parker and has been diagnosed with radiation poisoning. Peter himself is feeling the effects from being exposed to the irradiated Molten Man himself. In spite of this, when he becomes aware of the Molton Man's presence, he changes into Spider-Man to battle his foe. Spider-Man holds him at bay with a fire-hose prompting him to escape, and Spider-Man is forced to flee himself when the police arrive. Returning back to Mary Jane's apartment, Spider-Man eavesdrops on MJ's conversation with Liz Allan. Liz explains that after graduation from high school she took a job as a nurse to look after her stepbrother, the Molten Man. However, when the Molten Man finally got fed up and escaped from medical care, he lost access to the medication that was keeping his molten skin from melting away. Spider-Man changes back into Peter Parker, and sneaks through MJ's neighbor's apartment, getting his pant leg torn thanks to the neighbor's dog. Peter checks in on the women and departs when MJ tells him she's taking Liz Allan out for dinner. When Peter arrives at the Bugle the next day, Jameson (furious as usual) tells him to go to the location of another robbery which has the Molten Man's trademark. When Peter tries to get information from one of the workers cleaning up the site, it gets him nowhere. When he calls Ned in the hospital to learn anything new and check on him, he learns that the Molten Man stole a chunk of radioactive meteor. Checking out the robbed warehouse as Spider-Man, he learns that it had recently taken in a shipment of radioactive materials for medical treatments, and realizes that the Molten Man has been stealing these items to prevent himself from melting away. The police soon arrive and chase Spider-Man off. Deducing that the Molten Man will rob another museum that has a similar meteor fragment as the one that turned him into the Molten Man, Spider-Man catches the Molten Man in the act. The Molten Man makes a run for it, dawning one of his melt-proof disguises and hopping on the subway. However, his powers have gotten too out of control and they burn away his disguise. Spider-Man tracks him down. As they fight on the roof of the train as it crosses a bridge, the Molten Man's deterioration gets even worse. As the two fight, Spider-Man knocks the Molten Man's bag full of stolen isotopes and meteor fragments off the bridge and into the water below. Molten Man, in desperation, dives down, in spite of Spider-Man's warning that exposure to the cold water would destroy him. Spider-Man can only watch in horror as the Molten Man seemingly dives down to his own demise.