The original ending of Todd Phillips' Joker had Arthur Fleck give himself similar facial scars to the ones that Heath Ledger had in The Dark Knight.

The original ending of 2019’s Joker was apparently going to make a heavy reference to The Dark Knight. We didn’t get to see it, however, because The Dark Knight’s director Chris Nolan vetoed it. In a report by THR,

There are few greater examples of this than Heath Ledger’s take on The Joker in 2008’s The Dark Knight. Ledger took the Clown Prince of Crime and took away anything fancy or shiny. This was not a man who made clues based on Looney Tunes animators and could kill you with a pie.