That’s why “Under the Red Hood” — and technically “Hush”, since it was established after the fact that he was involved, even though the Jason Todd who appeared there was Clayface ...

And while being tortured by Hush, possibly ripping out the Joker's tongue, still flapping his feet around the place. And in doing so, reminding us of The Killing Joke by Alan Moore and Brian ...

Besides Hush, DC Comics has teased the Joker in the first issue (titled “The Pawn”) and, according to the cover for Batman #159, Jason Todd/Red Hood. Batman #158 variant cover and batman #159 ...