Spider-Man 3 included at least three characters.
Harold `` Harry '' Osborn is a fictional superhero and ex anti-hero in the . The character first appeared in The Amazing Spider-Man # 31 ( December 1965 ) , and was created by Stan Lee and Steve Ditko . Sandman ( William Baker a.k.a. Flint Marko ) is a fictional supervillain appearing in American comic books published by Marvel Comics . Spider-Man is a fictional superhero appearing in American comic books published by Marvel Comics . The Spider-Man series broke ground by featuring Peter Parker , the high school student behind Spider-Man 's secret identity and with whose `` self-obsessions with rejection , inadequacy , and loneliness '' young readers could relate . Spider-Man 3 . Following the events of Spider-Man 2 , Peter Parker has become a cultural phenomenon as Spider-Man , while Mary Jane Watson continues her Broadway career . Harry Osborn still seeks vengeance for his father 's death , and an escaped Flint Marko falls into a particle accelerator and is transformed into a shape-shifting sand manipulator .