No, it isn't some kind of twisted gag. Batman's arch-nemesis The Joker is actually getting a solo movie and it will be set outside of the mainline DC Extended Universe.
It's all part of the plan at Warner Bros, which is branching its comic adaptations out into multiverse movies free from the restrictions of a shared cinematic world.
Reports suggest the film will be an '80s-set origin story that fleshes out Mister J's madness and descent into clown-faced villainy. The Hangover's Todd Phillips is said to be attached as writer while Martin Scorsese could be producing, and that will hopefully spell a hard-boiled crime story with elements of dark comedy.
From what little there is to go off, the proposed Joker movie sounds promising, although the biggest risk they're running here is stripping the character of his mystery. The villain is at his best when depicted as a dehumanised force of chaos, and giving him a backstory might just compromise that.
Nevertheless, the project presents the opportunity to adapt some of the classic Joker origin tales from the DC Comics vault, and perhaps even one of the more astute fans theories the legendary bad guy has inspired over the years.