I want to start things off by stating that this is not another theory about Red Hood being in the Dc movies. Recently I finished playing through Arkham Knight, and I also recently re-watched Batman Beyond Return of the Joker. If you recall a couple of months back a picture of Dick Grayson's tomb stone was leaked I then combined that with the idea of somebody mentally becoming the Joker from Arkham Knight and Return of the Joker which gave me my theory. What if in the Zach Snyder universe Dick Grayson is the Joker (The second Joker atleast)? Before you go hating on my theory in the comments section let me explain my reasoning behind this. In the new trailer for Batman V Superman, we see and hear a few different things. We see a Robin costume that Joker has written on it "Jokes on you Batman" followed by Bruce Wayne saying "20 years in Gotham, how many good guys are left?" most would think that the line suggests Robin is just dead but you can easily turn it around to Bruce wondering how many people are still good, infering Robin went bad. Back to the suit in Return of the Joker Tim Drake is tortured by and evetually becomes the Joker and wrecks havoc on Barman Beyond. What if the theoretical original Joker In the Snyder universe tortured Dick Grayson and wrote his little comment in a litteral way Batman. Batman uses a kid to help to defeat Joker, Joker then would use the kid to hurt Batman by making the kid into another Joker, it would be worse than killing Robin. Then there is the newspaper that has "You let your family die written on it" in Joker styled writting everybody seems to think it's Red Hood but if my theory is correct then it's Grayson/Joker using his knowledge from being Robin to mess with Batman to an extent the original joker couldnt. Bruce probably knows it is Dick hence the tomb stone that got leaked, whenever the first Joker tortured Robin, Dick Grayson died, and the second Joker was born and Batman treats that in a litteral manner, kind of like how Jason Todd's Robin suit remains on display in the Batcave and his tomb stone remains as if he were still dead because in a way Jason is still dead, same concept here with Dick. Now to my last bits of evidence that are less compeling but I think are worth mentioning. When Jared Leto prepared for the role of The Joker he beefed himself up, but since when does the Joker ever look muscular he all ways seems to be the scrawny guy, but if he were a crime fighter being buff might have helhimself plus when Leto is normal looking he looks like he could have played Nightwing. My final reason to support my theory is the way the whole Snyder Universe is shaping up if you look at man of steel and how it was pretty dark, then at the suicide squad trailer which looks really dark, even Batman v Superman looks like it will have a pretty dark tone to it, Robin becoming the Joker would add another layer to that really dark universe plus add a really cool plot twist if I do say so myself, and be a cool reference to Batman Beyond. My theory has some holes like what happened to Joker number 1. But I want to see what other people think and if they have anything to add.