There are those who believe that The Joker used to be Robin in the world of Batman v Superman: Dawn of Justice and Suicide Squad. While that may sound ridiculous, it's worth bearing in mind that Dick Grayson went insane and became the new Joker in Frank Miller's The Dark Knight Strikes Back, so there's certainly precedent for this happening in the comics (especially as Zack Snyder is using The Dark Knight Returns as his inspiration). Surely the director won't shake things up that much?
Well, Batman asking Aflred in the Batman v Superman trailer "20 years in Gotham, how many good guys are left? How many stayed that way?" led many to believe that The Joker could be his former sidekick from early on, and now one redditor has pointed out the following which seems to once again link the two characters; they have matching scars. Could this Joker be a second generation version of the Clown Prince of Crime?! I don't think so to be honest, but it would explain the Robin tattoo and why this version of The Joker is so different to what's come before. This feels like a reach, but what do you guys think? As always, thoughts and theories in the usual place please!