A giant in the world of comic books, Lee is the former president and chairman of Marvel Comics and the creator of numerous comic book superheroes. With several artist collaborators, Lee co-created Spider-Man, the Fantastic Four, the X-Men, Iron Man, and the Incredible Hulk, among many others, and is credited with introducing complex, naturalistic characters into superhero comic books. Lee has made cameo appearances in what films featuring characters that he helped create? Discuss