At the time of Batman & Robin's release, publications remained optimistic about the future of the franchise, with industry stalwarts like Variety awkwardly bleating, "It's certain that the series will continue on." Warner Bros. had planned a fifth Bat-pic, which Schumacher was on board to helm. However, screenwriter Akiva Goldsman had wisely stepped away from the project.

Known as Batman Unchained, this fifth and notoriously cancelled film sounds like it had the potential to be even more bonkers than Batman & Robin. Schumacher has stated that the film "would have been very dark," with none other than professional scenery chewer Nicolas Cage lined up to play madcap psychiatrist Dr Jonathan Crane (aka the Scarecrow). 

Much how the character was explored in Chris Nolan's Batman Begins, Batman Unchained was said to follow Batman confronting the demons of his past and conquering his fears after being exposed to Scarecrow's fear toxin. Former Batman stars Michelle Pfeiffer, Jack Nicholson, Jim Carrey, Tommy Lee Jones, and Danny DeVito were even rumored to reprise their roles during a cameo-stacked hallucination sequence. 

A secondary antagonist was also planned in the form of Harley Quinn. Bizarrely, the character was reimagined in the script as a toymaker who discovers that the Joker is her father. Even weirder, '90s rivals Courtney Love and Madonna were both rumored as casting considerations for the role, which is actually kind of genius. In fact, we're kind of disappointed we never got to see this madness on the silver screen.