The Joker infects fish with laughing gas. After not being allowed to copyright his Joker Fish, he targets the innocent bureaucrats who told him that copyright doesn't work that way.
Tropes in this episode include:
- Adaptation Amalgamation: The episode is mostly adapted from the comics storyline "The Laughing Fish"/"Sign of the Joker!" (Detective Comics #475-476), however, the final act is largely drawn from the unrelated comic story "The Joker's Five-Way Revenge" (Batman #251).
- Adaptation Distillation: This story primarily adapts Detective Comics #475-476 and cuts out pretty much all the subplots carried over in the previous issuesnote The episode swaps out this climax out for the aquarium showdown from the otherwise-unrelated Batman #251. There are a few changes to the plot outside of the deleted subplots:
- The inclusion of Harley Quinn and Harvey Bullock;
- The clerks targeted by the Joker were killed in the original (in the adaptation, Batman was able to administer an antidote to the Joker venom in time);
- The televised warnings from the Joker are much more ominous and lack the "humorous commercial" angle;
- There was a third attempted assassination, with Joker trying to sneak into get at his target dressed as a cop (sound familiar?). Batman foils this by use of a device dropped by Hugo Strange's ghost, leading to a fight on a construction site, where Joker seemingly falls to his death. This was the original ending, presumably changed due to it being too intense, or the integral wrapping up of the Silver St. Cloud and Rupert Thorne subplots note
- Adults Dressed as Children: Two of Joker's henchmen are dressed as 1950s-era children (one with a beanie, one with Girlish Pigtails) for Joker's commercial for "Joker Fish" - and they did not enjoy it. Harley played their mom.
- Artistic License Law: In-universe, the Joker is mistaken when he thinks that he can patent fish because they bear his image, and when the patent clerk tells him so, he decides to kill him. Possibly an aversion, as Batman himself believes Joker knows the law doesn't work that way and is just using it as an excuse to carry out a terror campaign for his own amusement.
- Even worse, his plan was to copyright (not patent) the fish so that anyone catching them would have to pay him a royalty. That's not how copyright works. (And since the fish were going to be released into the wild, he obviously didn't have any issue with unauthorized reproduction...)But again, it's probable the Joker knew this all along and was just doing it all For the Evulz...
- Bait-and-Switch: For a moment it looked as though Batman was affected by the Joker venom (via cat scratch), until we see it's the second clerk in Batman's suit.
- Body Double: Batman tries to protect one of the Joker's targets by disguising himself as him and putting the actual target in a Batsuit. It fails because the target's cat, bearing a load of Joker venom, still recognizes its human.
- Broken-Window Warning: It's not a rock, but one of the poisoned Joker Fish (a swordfish) that comes through the window of a predicted victim's home.
- Disproportionate Retribution: The Joker introduces his "smile" toxin into the fish supply of Gotham Harbor, hoping to copyright the red-lipped, grinning ichthyoids and sell them in supermarkets. When told that he cannot copyright fish because they are a natural resource, he retaliates by carrying out an elaborate scheme to kill everyone in the Gotham City patent office until he gets his way.
- Does Not Like Spam: Harley's dislike of fish is mentioned here for the first time. It will come up again later.
- Do Not Adjust Your Set: Joker launches a series of commercials to "warn" the unfortunate clerks who are being targeted, and to mock Batman. The first time it happens, Bullock orders the channel changed, but the "it's on the same channel" part happens. The second time, Batman angrily turns off the TV while Harley sings the commercial tune.
- The End... Or Is It?: Played with. The Joker falls into the ocean very close to a hungry shark. Commissioner Gordon asks Batman a bit later if he thinks the Joker's really dead. Batman says he wishes so, but that he has his doubts. The camera closes in on the Joker card that Harley has thrown into the ocean in mourning and then it's eaten by the same shark, managing to make the viewer certain both that the Joker survived and that he did so only by the skin of his teeth (so to speak) at the same time.
- Everyone Has Standards: Bullock has little love for Batman, but he thinks it's inhuman for the Joker to toss him to the shark.
- Failed a Spot Check: The Joker's elevator chair might have made a better escape method if he'd checked to see if the skylight was open before activating it.
- Force Feeding: A comedic example. Joker is doing a commercial for his new brand of Joker Fish, and tries to get Harley to eat one to show how good they are. Harley sheepishly protests that she's got a problem with fish, but Mr. J just shoves it in her mouth. She manages to grunt out, "Yummy-yum-yum," before running offscreen to hurl.
- For the Evulz: Given that the Joker made preparations to spray G. Carl Francis with the first part of his binary toxin even before his demands were rejected, it's implied that he expected as much and is perfectly willing to settle for killing a load of people in clever ways if he can't get his money. Batman explains this to Francis later, telling him that killing a harmless, powerless bureaucrat is just the villain's idea of a good joke.
- Gratuitous French: Albeit mispronounced. When the Joker introduces Harley to Mr. Francis, she says, in her "Noo Yawk" dialect, "En-chaan-tee", clearly meaning to say, "Enchanté."
- Instantly Proven Wrong: With police everywhere, Bullock boasts that no one is getting into Francis's house tonight. Batman then immediately reveals that he sneaked in disguised as an officer and that it was easy to do so, too.
- Insult Backfire:Bullock: Come on, he [the Joker] was a demented, abusive, psychotic maniac!
Harley: Yeah. [sob] I'm really gonna miss him.
- Latex Perfection: Batman's disguise as the second Joker target.
- Mermaid Problem: The Joker seems to be flirting with Harley Quinn by asking her to "be [his] little mermaid." He then puts a giant fake fish head over her head, to which Harley responds, "You're really sick, you know that, boss?" Funny this got past the censors.
- Mythology Gag: Like in the 1989 film, Joker's venom becomes effective when two or more components are mixed.
- Never Found the Body: Joker is last seen falling near the shark. Nonetheless, Batman can't shake the feeling that he somehow survived.
- Oh, Crap!: The Joker jumps into the ocean, completely forgetting about the shark that had recently been released:See, Batsy, I think of everything! Hahahahahahaha— AAAAAAAAAAAAHHHHHH!
Francis: Great Scott!
- Also, when the Joker arrived in Mr. Francis' office.
Joker: Actually I'm Irish.
- Batman after Francis mentions Harley sprayed him with a concoction earlier: "GET THIS MAN TO A HOSPITAL! NOW!"
- Pragmatic Villainy: The Joker doesn't throw Bullock to the shark—at least not right away—because he realizes that if Bullock found the place, Batman will find it pretty quickly too. So he decides to keep Bullock alive a while to use as bait.
- Reality Ensues: As Bullock points out, it hardly takes a supercomputer or a Sherlock Scan to realize that an exotic fish probably came from an aquarium.
- Shark Pool: The Gotham Aquarium is closed for renovations, so the Joker takes it over so he can feed people to its sharks.
- Shout-Out: Joker pulls a wrench out of a box with the words "Binford Tools" written on it.
- Spared by the Adaptation: The episode loosely adapts a 2-part comic story of the same name. In it, the Joker infects two random victims with a lethal dose of his joker venom. In the TAS version, since broadcasting standards wouldn't allow the writers to kill someone in a children's cartoon (at least not onscreen), instead Batman is successfully able to administer an antidote to the venom after both get infected. Doesn't make the scene any less freaky, though.
- Squee!: Harley, when Joker says he's gonna make her his little mermaid.
- Talk Like a Pirate: Joker indulges in this during his commercial.
- Threatening Shark: Bullock's suspended over a Shark Pool and then Batman has to fight the shark. At the end Joker is apparently eaten by the shark, but we all know how that turns out.
- You're Insane!: