8 Mysteries Even Batman Couldn't Solve
2. How The Joker Returned - Batman Beyond: Return Of The Joker
It wasn't just one Batman who couldn't solve this mystery, but not even two Batmen could crack the code behind the core plot of the stunning Batman Beyond: Return of the Joker animated movie.
Released in 2000, this picture takes place in the 2040s landscape of the Batman Beyond show. With Terry McGinnis the present-day Batman, operating under the stewardship of Bruce Wayne, this future-set offering is thrown for a loop when the long-deceased Joker reappears to cause chaos.
The mystery element here, is just how exactly is the Joker alive and well 40 years after he took his last breath? Neither Terry nor Bruce can decipher this situation, and even more problematic is this resurrected Clown Prince of Crime knows all of his old rival's secrets, including that his Batman is Bruce Wayne.
It would be revealed that the Joker had implemented a genetic chip in Tim Drake during Drake's younger days as Robin, with this chip turning the older Tim into a replicate of Mr. J. This scheme is shut down by Terry's Batman before Joker can fully take over Tim's body, but the only reason we find out the truth to this mystery is because the Jester of Genocide himself decided to let everyone in on his masterplan.