[1] The episode features the first appearance of the Joker's sidekick and love interest Harley Quinn, who was later introduced into the Batman comic book and eventually become a popular character in her own right.
Joker agrees to let him go and makes Charlie promise to do him a favor in return, taking his driver's license.
Two years later, Charlie has moved to Springdale, Ohio, and changed his name, but the Joker tracks him down to obtain the favor: helping him and Harley attack a testimonial dinner for Commissioner Gordon.
They then place a bomb on Gordon's chest, then bid farewell to Charlie, whose hand is glued to the door handle.
In 2012, Steven Padnick of Tor.com praises Mark Hamill's acting and cites Ed Begley Jr.’s "second great guest performance in a row" as Charlie.