There are some pretty significant clues in Joker which allude to the possibility that Fleck isn’t just some alternate universe version of the Clown Prince of Crime, but that he is in fact more of a proto-Joker, an extremely troubled man who will go on to influence the guy who will eventually cause the entirety of Gotham’s underworld to tremble at the mention of his name. Just in case you haven’t caught the movie yet, we will be getting into spoilers for Joker here, so please be advised.
It’s been posited that many of the events of Joker take place solely in Fleck’s troubled mind, such as his murder of talk show host Murray Franklin on live television and his incitement of a violent insurrection in the streets of Gotham. We already know that his relationship with his kindly neighbor Sophie was a pure fantasy; the actual Joker is many things, but he’s not usually depicted as being flat-out delusional.
Consider also that Fleck seems supremely uninterested and disconnected from organized criminal activity, and it’s pretty tough to picture him — as psychologically fragile as he obviously is — rising up to take over Gotham’s underworld. Add to all of this the fact that he’s presented as being literally decades older than Bruce Wayne; if Fleck’s universe will one day see the Batman going toe to toe with the Joker over the heart and soul of the city, then that Joker is unlikely to be Fleck, who will be a senior citizen by the time Wayne dons the cape and cowl.
Fans have noted all of these things since before Joker was even released — but do they add to our rumor’s credibility?