As a new experiment in rehabilitation (and a reward for the Joker's (initial) cooperation during the Red Hood spree), Dr. Quinn allows Arkham's inmates to hold a talent show. In attendance are Bruce Wayne, Dick Grayson, and Barbara Gordon, as well as the GCPD's top brass, who are alternatively amused and annoyed by the performances - until the Joker's stand-up routine reduces them all to helpless laughter. Unfortunately, this laughter stems not from comedic talents, but criminal ones; in collusion with Catwoman, the Joker had secretly stolen Professor Overbeck's brain regulator, and modified it to cast his brainwaves over whole crowds.
