The Laughing Fish (episode)

"The Laughing Fish" is the forty-sixth episode of. It first aired on January 10, 1993. Joker unleashes a toxin into Gotham City's harbors, causing all the fish affected to mutate into "Joker fish", with a deformed smile clearly resembling his own. Batman analyzes the fish and finds that the chemical is non-toxic to humans, so Joker is not trying to poison people. Instead, his plans are far more bizarre: he attempts to copyright the fish, and thus gain a percentage over all sold in the Gotham area

Plot
The catch of the night comes in and the fishermen take a look. They are horrified and disgusted to see that every fish is white with green fins, and has a huge Joker smile. Batman watches from afar and mutters, "He's made his move."

While Batman returns to the Batcave and analyzes a Joker Fish, the Joker goes to the Gotham Office of Copyrights. He heads up to a random worker, Mr. G. Carl Francis, and starts to talk business. However, he warns Francis not to speak, and hits him with a fish to drive home his point. This prompts Harley to spray him with a "perfume" to rid him of the fish smell. Joker explains his plan: since all fish in Gotham Harbor now bears his likeness he is entitled to royalties. Bewildered, Francis tells him that fish are a natural resource and cannot be copyrighted. Angered, Joker gives Francis until midnight to change his mind.

Back in the Batcave, Batman learns that the toxin only affects fish. Just then, a commercial for the Joker fish comes on and Joker repeats his threat against Francis.

Alerted, the police set up guards around Francis in his house. Bullock is confident that the house is secure, but Batman slips in easily, and reveals that if he snuck in easily enough, the Joker will too. Outside, a Joker van with a swordfish on top drives up.

Inside, Francis, making small talk, mentions the "perfume" Harley sprayed him with. Batman immediately shouts at Gordon to call an ambulance, but just then, the van launches its fish, rocket-propelled, through the window and into the room. It sprays a gas, and, when Francis breathes it, he begins laughing hysterically and a Joker grin appears on his face. Fortunately, Batman is able to inject him with an anti-toxin. Batman explains that the gas that Francis breathed was one part of a binary compound, and the Joker had already exposed him to the other part (the "perfume" that Harley sprayed).

Joker then appears on the television and announces the name of his next target, copyright office bureaucrat Thomas Jackson, unless his demands are met by 3 A.M.

Again, the police and Batman try to protect Mr. Jackson, this time with Batman acting as a decoy for Jackson. But the Joker sends Jackson's cat into the room, carrying a Joker fish, and the cat knows immediately who its master is, and attacks, scratching Jackson and poisoning him with the same toxin.

Both Francis and Jackson have survived, but Bullock is tired of waiting for the next attack and takes matters into his own hands. After he storms out, Batman notices that the Joker fish the cat was carrying is an exotic Japanese species, not native to Gotham Harbor.

Bullock enters the closed harbor aquarium. However, Harley finds him and takes him captive. The Joker then starts to lower Bullock into a tank with an enormous shark, but realizes that Batman will arrive soon and he's the one Joker really wants.

As predicted, Batman arrives and persuades Joker to allow him to switch places with Bullock. The Joker eagerly agrees and drops him in the pool, then shoves a lump of hamburger into Bullock's hands and pushes him in after Batman. The shark is instantly attracted to the blood from the hamburger but Batman manages to straddle the shark and uses his wrist shackles as an impromptu bridle, allowing him to steer the shark into the side of the tank, breaking the glass and spilling himself and Bullock onto the aquarium floor, and the shark into the bay outside.

Batman then heads to the roof to face off with Joker. Joker attacks Batman with a wrench, but Batman ultimately outdoes him and Joker is left with no place to run. Facing arrest (again), he jumps off the roof towards the harbor below. On the way down, he blows up a rubber ducky life preserver, laughing up at Batman that "I think of everything!" But his laugh dies when he sees the shark circling in the water below him. He plunges into the ocean, and the shark dives after him, apparently devouring him.

Commissioner Gordon then arrives to round up Harley Quinn and the remaining goons. Gordon asks Batman if he believes the Joker is gone for good. Batman looks out to the sea, and bluntly responds that as much as he wishes it were true, he doubts it deep inside. Indeed, the shark dives in and out of the water, but there is no trace of the Joker, dead or alive.

Production Inconsistencies

 * Few toothed fish have the large, flat teeth required to make the Joker's smile. The fish that Joker mentioned such as smelt and tuna are not amongst these fish and therefore the toxin should not have worked on them.
 * When the Gotham Times spins into screen and zooms in on the Joker's picture, his chin is straight, not following the rest of the folded newspaper. When Alfred reads the paper folded out, Joker's chin is exactly the same.
 * When Batman fires his grapple gun at the ceiling of the aquarium, the "clink" of the grapple catching is heard while the wire is still wrapping around the pole.

Trivia

 * The episode is based on the comics stories "The Joker's Five-Way Revenge" (Batman #251, September 1973) by Dennis O'Neil, and "The Laughing Fish" and "Sign of the Joker!" (Detective Comics #475/476, February/March 1978), by Steve Englehart.
 * It is also reminiscent of the Joker's first-ever caper in the comics: after he announced that he planned to kill a millionaire and steal a priceless diamond from the man's house, the police set up a protective ring around the millionaire, only to be baffled as the man dropped dead right in front of them. Batman discovered that Joker had broken in the night before, injected the sleeping millionaire with a slow-acting version of his Joker toxin, and stolen the diamond, replacing it with a fake.
 * It is one of three episodes with no title card, the other two being "Heart of Ice" and "The Demon's Quest".
 * Joker's mention of "Colonel What's-his-name" is a reference to Colonel Sanders, the founder of Kentucky Fried Chicken.
 * The Joker takes a wrench from a toolbox labeled "Binford Tools". A reference to the fictional tool company of Home Improvement. Although the label was partially obscured off the side of the screen, it was clear enough what it read out to be.
 * The first ever episode in the DCAU where the Joker is apparently killed but later returns alive and unharmed, other examples being "Batman: Mask of the Phantasm", "World's Finest", "Mad Love", "Wild Cards" and "Batman Beyond: Return of the Joker" (see "List of characters that have cheated death").