Due to the Joker virus spreading across Gotham driving its people insane, Batman and the remaining sane citizens of Gotham were forced to take sanctuary in Arkham Asylum. There Damian enlisted Jackanapes help in discovering more about the disease and a possible cure. After Damian gave him the DNA of a baby who appeared to be unaffected by the Joker virus, an enraged Jackanapes informed him the baby was the carrier of the virus.
Jackanapes, alongside other residents of Arkham, engaged in a short lived battle with the Joker-crazed citizens of Gotham. This battle, as well as the life of Jackanapes, ended when Doctor Hurt (as POTUS) detonates a bomb which destroys all of Gotham and its inhabitants.