15Ang Lee's Hulk 2
These days, the incredible Hulk is best known for his role in the Avengers movies, where Mark Ruffalo is either buddying around with Robert Downey Jr., or knocking down giant alien dragons with one punch. But back in the early days of the superhero revolution, Hulk was the subject
of a love-it-or-hate-it arthouse film from Ang Lee, where the director of Crouching Tiger, Hidden Dragon attempted to do something dramatically different with the superhero genre. Though the film divided fans upon its release, both Lee and Oscar-nominated screenwriter James Schamus were already putting together plans for a sequel before the first one came out.
Not too much is known about the Hulk sequel that never happened, but Schamus did reveal that they were planning to have Banner transform into the grey Hulk (often called "Joe Fixit" in the comics) for at least a portion of the film. In the years since, Schamus has revealed that the sequel would have taken place on a Native American reservation, and would have been a politically-charged film that was going to be "all about radioactivity." Later on, of course, plans for a Hulk sequel were replaced by a reboot once Marvel got the rights back, though some traces of the original sequel concept remain in the finished film.