Vincent Stegron was hired by S.H.I.E.L.D. to work with Dr. Curt Connors to study dinosaur DNA from the Savage Land. Obsessed with the experiments Connors did to create the Lizard, Stegron stole the dinosaur DNA and injected himself. In moments Stegron was turned into an orange stegosaurus type creature. Now bent on turning all humanity into creatures like himself he took several dinosaurs with him from the Savage Land to New York. There he encountered Spider-Man, Black Panther, and Ka-Zar. During the battle that followed Stegron was beaten by being knocked into a nearby river. Months later Stegron returned and blackmailed Connors into helping him restore several dinosaur remains from a museum. Connors did what Stegron asked and accidentally turned into the Lizard. The two reptiles clashed as Spider-Man showed up and put Stegron into hibernation using the extremely cold temperatures the weather was producing. Months later Stegron, now back in his human form, woke from hibernation and wandered New York. During a battle between the Vulture and Spider-Man, Stegron regained his powers and joined many of Spider-Man's enemies in an all out battle to defeat him. However Stegron was knocked unconscious and was taken in by the authorities.
Stegron managed to escape and headed back to the Savage Land. While in the Savage Land he took over a S.H.I.E.L.D. installation which drew the attention of Thunderstrike, the Black Widow, and the Black Panther. During the battle over the installation Stegron was forced into an extremely cold environment and again went into hibernation. Sometime later Stegron managed to awaken from his slumber and terrorized Roxxon Oil, who was illegally drilling in the Savage Land. Soon Stegron was opposed by Ka-Zar, Shanna The She-Devil, and Spider-Man. During the battle the Hulk and a gigantic bird creature known as Chtylok arrived and helped Stegron fight off Roxxon Oil. The heroes then joined forces with Stegron when they realized he was trying to protect the Savage Land. Eventually Stegron managed to scare the Roxxon agents and was left in peace in the Savage Land.
Sometime later Stegron, reverted back to his human form, exiled himself to wander the Arctic Circle when he stumbled upon the Rock of Life. Inspired by its de-evolving abilities, he took it with him back to New York where he slowly began to transform back into his dinosaur form. He then sent the Rock to a friend of his who then put it on display at the Museum of Natural History in hopes that it would devolve the inhabitants of New York City into prehistoric creatures like himself - with him as their leader. As a result, various heroes and villains with connections to the animal kingdom such as Spider-Man, Puma, Black Cat, the Vulture, Lizard, Man-Wolf (John Jameson), and Vermin were affected by its power, causing an increase in their savagery. However Spider-Man maintained control, and discovered Stegron's plans at the museum where the two battled. With the help of Mister Fantastic and the Invisible Woman Spider-Man managed to stop the Rock's powers from reaching others in New York using a piece of his armor. He then beat Stegron into submission. Stegron was then taken into custody by the authorities as the Fantastic Four placed the Rock in a secure vault in the Baxter Building.
