Gotham citizens are bursting into hysterical laughter and dumping their stolen goods into the river, and Batman, Robin and Batgirl is soon on the trail of The Joker, who is using a steam train to commit his new crime wave.
Tropes for this episode include:
- Brainwashed and Crazy: Anyone who rides the city train will undergo a hypnotic trance after a certain time where the victims laugh like mad as they commit crimes for Joker.
- Demoted to Extra: Commissioner Gordon’s one appearance in this season.
- "Eureka!" Moment: After Bruce, Dick, and Barbara had also fallen victim to Joker’s latest scheme (but having been intercepted by police before they could really steal anything), it’s seeing the news report and recognizing the people shown throwing their stolen goods, they realize Joker’s using the commuter train, specifically the flickering lights, to hypnotize his victims.
- Even Evil Has Standards: Played With. When Joker has Batman, Batgirl and Robin trapped in a cage in the mining tunnels under Gotham, Robin makes the expected guess that Joker’s going to run them over with his train. Joker responds that even he wouldn’t do something that obvious.
- Oh, Crap!: Robin has this reaction at the beginning of the episode. When he and Batgirl are discussing theories on how Joker’s affecting the victims, she begins laughing uncontrollably, meaning Joker somehow got to her, too.
- Plot Armour: Despite being caught stealing on camera, Bruce, Dick and Barbara are all let off from stealing, due to being part of a string of strange behaviour.
