Casting is truly an art form. What would Tony Stark be without Robert Downey, Jr., who had to fight to be cast? And what would Marvel be without Iron Man's raging success?
Here's a collection of 50 celebrities who almost played superheroes. Some were pursued by the studios but turned the roles down, while some of the comic book movies just never got made altogether. Which of these stars do you wish you had seen in Marvel hero and villain roles? Cast your votes below!