Hey look... Joker's childhood, with a crazy and abusive aunt... for some reason, during a Zoo related crime a few years back, Joker gets reminded of his aunt, and starts to think about family. He spies a young gorilla, looks at it longingly, and decides it's time to start his own family, starting with the gorilla who will eventually come to be known as Jackanapes.
Joker trains Jackanapes to be the evil Gorilla we've seen in the Batman #666 timeline, somewhat mirroring Joker's own twisted childhood. Eventually, a Gotham councilwoman aims to shut down the Gotham zoo, something Joker takes offense to, so he and Jack board their blimp during an air inspection. Joker plans to use some sort of radio wave thing to scramble their brain, and Jackanapes seems sad for some reason, but then the people they're attacking sort of mutate into monsters... The monsters tackle Joker and Jack out of the blimp, and Joker manages to pop the wings on his wing-suit, but Jack doesn't, falling into the water below. Joker is sad for a moment, but then laughs, as he finds it funny he's going to need refunds for all the swimming lessons.