Batman: Death in the Family is a forthcoming animated short film due out digitally on Aug. 23 and presumably HBO Max soon after. It's based on the iconic comic book storyline in which the Joker murders Robin and contains much of the same voice cast from Batman: Under the Red Hood, one of the most celebrated DC Universe movies ever made. But most interestingly of all, it will be a choose-your-own-adventure showcase with a branching storyline.
Much like Black Mirror: Bandersnatch from Netflix, viewers will be able to make various decisions on behalf of the characters and see it play out in realtime. It's something we expect to see a lot more of over the coming years, especially with niche genre productions like this one.