The film begins with Peter Parker basking in his success as Spider-Man, while Mary Jane Watson continues her Broadway career. Harry Osborn still seeks vengeance for his father's death, and an escaped convict, Flint Marko, falls into a particle accelerator and is transformed into a shape-shifting sand manipulator. An extraterrestrial symbiote crashes to Earth and bonds with Peter, influencing his behavior for the worse. When Peter abandons the symbiote, it finds refuge in Eddie Brock, a rival photographer, causing Peter to face his greatest challenge.
Spider-Man 3 was commercially released in multiple countries on May 1, 2007, and released in the United States in both conventional and IMAX theaters on May 4, 2007, by Columbia Pictures. Although the film received mixed reviews from critics, in contrast to the previous two films' highly positive reviews, it stands as the most successful film in the series worldwide, Marvel's most successful film, and Sony Pictures Entertainment's highest grossing film to date. The film has been rated PG-13 by the MPAA in the United States and 12 by the BBFC in the United Kingdom for Sequences of Intense Action Violence.