“”Superhero”” has been jointly trademarked by DC Comics and Marvel comics. The most valuable comic book in the world is Action Comics #1 which includes the origin and first appearance of Superman. Kryptonite made its first appearance on the Superman radio show, not in the comic book. Superman is 6 feet 2 inches tall. Wonder Woman’s bulletproof bracelets were made of a metal called feminum. Marvel comics put a hyphen in Spider-Man’s name so he would not be confused with Superman. Captain Marvel’s appearance was modeled after actor Fred MacMurray.