Mary Jane Watson, often shortened to M.J., is a fictional supporting character appearing originally in Marvel comic books and later in multiple spin-offs and dramatizations of the Spider-Man titles as the best friend, love interest, and one-time wife (as Mary Jane Watson-Parker) of Peter Parker, the alter ego of Spider-Man, after the death of Gwen Stacy. Initially, upon her introduction, she had a friendly rivalry with Gwen for Peter's affections.