Johnny Anvil was a prisoner chained to Hammer and were linked together at the wrists. They manage to escape prison and run into an alien that is suffering from some injuries. Hammer shoots the alien with a .38 caliber pistol he took from a guard. The alien does not die but actually recovers because it absorbs the metal and sustains the alien's internal existence support systems. The alien repays the two convicts by transforming their chain into an energy synthecon and grants them superhuman strength. Hammer and Anvil return to the prison to exact vengeance but run into the Hulk. During the fight, the Hulk manages to break the energy synthecon and the two men went insane since they were both physically and psychically linked. The two convicts are apprehended and sent back to prison. During a battle with the Hulk Hammer is shot in the face with an explosive bullet by Scourge of the Underworld who was disguised as a Native American Shaman. Having been linked by the synthecon to his dead partner, Anvil died soon afterward.
Anvil was created by Len Wein and Herb Trimpe in 1974 and first appeared in The Incredible Hulk # 182.