Gerald Stone was one of a group of scientists conducting experiments to cure cancer by running tests on homeless people undergoing paid pharmaceutical trials. Stone held the theory that one could become immune to cancer in the same way as one can become immune to snake bites. He ran an unauthorized test on Jacob Eishorn, one of the homeless, with mixed results. Although the experiment was successful in that Jacob had become immune to cancer the bad side was that he became akin to a living cancer rotting anything he touched. Jacob who had also become mentally unstable, adopted the name " Styx", and could only find relief and pleasure in the death of others, needing their life force to survive.
Out of a sense of duty, Stone vowed to find a cure for Styx, and in order to find the money to do so the pair became mercenaries. Although he does not have any powers, he built himself some high-tech weaponry which included two large weapons on his shoulders that can fire a variety of things: energy blasts, blinding flash, sticky resin and knock-out gas. Stone hoped that in their line of work his partner would be able to satiate his needs on criminals and not innocent people.
The pair were defeated by Spider-Man during their first assignment as hired thugs on a mission to capture Mary Jane Watson, for obsessed millionaire Jonathon Caesar. The pair then failed in their attempt to kill Spidey while he was being hunted by Venom, resulting in them being sent to prison.
Stone was offered a possible cure for Styx’s illness by an old friend Dr. Elias Wirtham, who unknown to him was also the vigilante Cardiac. Far from providing a cure, Cardiac tried to kill Styx convinced that he couldn’t be redeemed. Spider-Man stepped in to stop the Cardiac and Styx and Stone returned to prison.
Stone was created by David Michelinie and Todd McFarlane in 1988 and first appeared in The Amazing Spider-Man # 309.