The Joker unleashes a lethal laughing gas in Gotham City that, when exposed long enough, will drive everyone to insanity.
* CapeSnag: A version of Batman's detachable clasp is shown when his cape becomes trapped in the grip of a robot Joker henchman -- Batman quickly detaches his cape and spends the rest of the episode capeless.
* DisproportionateRetribution: Inverted, after Batman destroys the Joker's pet robot, Captain Clown (which Joker considers murder, since Captain Clown was his best friend). Joker retaliates by.... [[PokeThePoodle dumping a forklift full of smelly garbage right on top of Batman]].
* GettingCrapPastTheRadar: Captain Clown's MechaMook status (see below) allows for him to be dispatched in a manner that'd be impossible to show with your standard flesh and blood henchman. It also allows Joker to avert the NeverSayDie clause and chastise Batman for "killing" him.
* IKnowKungFaux: One of Joker's goons tries to intimidate Batman with quasi-martial arts posing and yelling "Hi-ya!". Batman effortlessly puts him down in about 3 seconds.
* LargeHam: The Joker gets a few extra-hammy ones, "You ''KILLED'' Captain Clown!!!!" and "Your going to melt just like a grilled cheeeeeeeeeeeese sandwich!!!"
* MechaMook: The "Captain Clown" robot piloting Joker's laughing-gas barge.
* PricelessMingVase: Alfred smashes a Ming (he had been driven mad by one of The Joker's poisons) and afterward felt ashamed, and was even prepared to accept being docked pay from Bruce Wayne as punishment.
* PunchPunchPunchUhOh: When Batman realizes that Captain Clown is really a [[MechaMook robot]]