Little is known about Jennings' early life. He revealed that he was bullied as a child and thus hated the word "freak", and that he eventually fought back against the bullies until they left him alone. He kept his mutant powers a secret and eventually got work as a stuntman. After injuring the lead actor during a movie shoot and promptly being fired, Jennings was hired by Mysterio to take down Spider-Man in exchange for a large sum of cash. Given the name Hardrock by Mysterio, Jennings ambushed Spider-Man on a rooftop after the webslinger was lured there by Mysterio. Jennings easily overwhelmed Spider-Man and knocked him out. Before Jennings could kill Spider-Man with a bullet to the head, Spider-Man's black costume came to life and killed Jennings by entering his mouth and exploding his head.