Joker 2: The Musical

The speculation is that in the same way the first one drew from and paid homage to Scorcese's Taxi Driver and King of Comedy, Joker 2 (supposedly to be titled Joker: Folie á Deux) will draw from and pay homage to Scorcese's New York, New York.

Could be brilliant, could be unwatchable, but it'll be something we've never seen before. I can imagine a scenario where the musical numbers only come when the film is shown from the perspectives of Harley and the Joker, as a way to depict their shared insanity and warped view of reality. I think that could actually work really well.