When Peter and Mary Jane lived in the Bedford Towers, Jonathon Caesar kidnapped Mary Jane and attempted to force her to marry him. Mary Jane refused, and attempted to try and talk Jonathon Caesar out of it. In the end, she tried to electrocute him but luckily for him, he was wearing rubber shoes. He then pulled out a knife, but before he could made another move, she knocked him out with a lamp.
He later met his end when trying to corner Mary Jane. He was shot and killed by another of Mary Jane's obsessive fans, who was pretending to be a policeman at the time.
Jonathon Caesar was created by David Michelinie and Todd McFarlane in 1988 and first appeared in The Amazing Spider-Man # 304.