If you haven't heard of it yet, you should start getting very, very excited about Birdman.

Ostensibly a black comedy, it's a meta-drama exploring the weirdness of acting, audiences, critics, cinema, superhero movies and much more through the story of an actor (Michael Keaton) - famous for portraying an iconic superhero - as he struggles to mount a Broadway play. In the days leading up to opening night, he battles his ego and attempts to recover his family, his career, and himself.

Ahead of its release on January 1st, we take a look at 12 memorable superheroes that did not originate from a comic book.