[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/the_batman_superman_movie_worlds_finest_1997.jpg]]
[[caption-width-right:350:[[Film/BatmanVSupermanDawnOfJustice No relation.]]]]

This episode, released on home video as ''The Batman/Superman Movie'', is the first crossover with ''WesternAnimation/BatmanTheAnimatedSeries'', with Franchise/{{Batman}}, ComicBook/TheJoker and ComicBook/HarleyQuinn appearing in Metropolis.

The Joker has recently robbed an antique jeweler in Gotham, and was last seen outside of Metropolis. Curiously, the only thing he stole was a jade dragon statue. Luckily, Bruce Wayne is currently visiting ComicBook/LexLuthor as [=LexCorp=] and Wayne Enterprises are in a joint project, developing robot drones for space travel. Luthor is interested in [[KillerRobot military applications]], which Wayne [[DoesNotLikeGuns disagrees with]]. Bruce Wayne meets Lois Lane (who had tried asking out Superman until a bank robbery took priority) and asks to take her out on a date, which Clark Kent does not approve of. Lois has even begun thinking of transferring to the Gotham City branch, and plans to talk about it during their date at a fancy restaurant.

It turns out the Joker is in Metropolis. After his DarkMistress Harley Quinn knocks out Luthor's NinjaMaid Mercy Graves, the Joker meets up with Luthor and offers him a simple deal: "Pay me one billion dollars and I'll kill Superman!" When Luthor asks how the clown can accomplish such a feat when Batman, who has foiled many of his scheme, has no powers, Joker reveals his secret weapon: the "Jade" Dragon he stole is actually a hunk of solid kryptonite excavated long ago. Under the promise that the criminal's actions don't trace back to him, Luthor hires Joker. The clown soon sets up a trap by kidnapping Lois during her date with Bruce.

Meanwhile, Batman tracks down the remains of the gang Joker overtook and it leads him to a night club. Superman disapproves of his JackBauerInterrogationTechnique, and Batman replies by throwing him across the room. Superman, in response, [[BullyingADragon shoulder-checks him into a wall in the blink of an eye]], and uses his XRayVision to discover his secret identity. Batman responds with Kryptonite and warns Superman that Joker has 20 pounds more where that came from. By the time Superman gets home and talks to Lois about her boyfriend, he sees a tracer on his cape, and Batman watching him from across town. Secret Identities have been swapped.

Superman heads off to rescue Lois and moves right into a trap at a [=LexCorp=] warehouse. The Joker presents him with half of the kryptonite dragon, but Superman's KryptoniteProofSuit holds firm... until the Joker splashes his suit with acid from his flower and begins torturing him in front of Lois Lane, leaving him to die. Luckily, Batman catches up, destroys the Kryptonite and saves both Superman and Lois. However, before they can capture Joker, he leaves behind a bagbof exploding marbles before he and Harely escape. Superman is able to get Lois and Batman out of there before the place blows up.

After Batman infiltrates Luthor's manner and scares the crap out of him, Luthor realizes the Joker left an obvious clue. He goes to [[YouHaveFailedMe directly confront the clown]] for an explanation. [[FunnyBackgroundEvent While Quinn and Graves]] have a CatFight, the Joker points out that he couldn't have anticipated Batman arriving and spoiling his plans again. Informing that he still has some Kryptonite left, the Joker doubles the price to kill them both. Luthor refuses and gives him one last chance to finish the job or their deal is off. The Joker hijacks one of Luthor's [[KillerRobot robot drones]] and sends it after Batman after distracting Superman.

Batman and the drone fight across Metropolis, finally arriving at the Daily Planet after hours, where Lois has been up finishing a report. Batman brings her and the drone into the printing press, and gets the drone and his cape stuck in a rolling press. This exposes his face to Lois, who isn't remotely pleased by this development. The drone recovers and is about to skewer Batman when Superman [[BigDamnHeroes returns from saving a sinking ship]] and [[GoombaStomp crushes the drone in a single blow]].

Luthor has invited the Joker to the warehouse where he was building his drones and his CoolPlane, the [=LexWing=] 5000. Why? Because Luthor has decided [[YouHaveOutlivedYourUsefulness the Joker is too much of a liability]] and plans to have him killed, then [[VillainWithGoodPublicity make up a story about how he killed a mass murdering thief stealing his technology]]. Instead, the Joker captures Luthor, takes the [=LexWing=] 5000 and prepares to destroy all of Metropolis while Luthor [[ForcedToWatch has a front-row seat]].

As Lois tends to Bruce's wounds, she expresses her frustration that she has been dating a superhero the entire time, especially since she can't publicize the discovery that Bruce and Batman are the same person. As she steps out for more supplies, Superman visits Bruce. With a chance to investigate the origin of the robots, Superman suggests a team-up.

They visit the same warehouse, and are greeted with a fleet of killer drones. Superman fights them off (including the KingMook with the other half of the Kryptonite statue and Mercy Graves as a HumanShield) while Batman flies after the [=LexWing=].

Batman catches up to the plane, breaks into it, and defeats the Joker. Unfortunately, the explosive marbles the Joker carried around start to detonate, blocking off their escape. Superman breaks in and rescues Luthor while Batman bails with Harley. Joker's explosive marbles go off again, and the Joker goes down with the [=LexWing=].

Wayne Enterprises has cancelled the joint project with [=LexCorp=] over ethical concerns and controversy, but Luthor is not directly tied to the events. Harley Quinn is extradited back to Gotham and Mercy Graves has the last laugh. Lois realizes her relationship with Bruce would never work out, but she does consider him a friend. Bruce and Clark note that they work well together, but Bruce will return to Gotham to continue what he does best. Before he boards a plane, he warns Clark not to upset Lois, because "I know where you live."

The episode had a [[https://vignette.wikia.nocookie.net/superman/images/d/d2/Batman_and_Superman_Adventures_Worlds_Finest_The_Official_Comics_Adaptation_Vol_1_1.jpg/revision/latest?cb=20161015154112 comic book adaptation]] that was extremely faithful.
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!!Tropes:
* ActuallyPrettyFunny: Invoked by Mercy:
-->'''Harley:''' ''(on TV, being shoved into a padded wagon)'' I want a lawyer! I want a doctor! I want [[TheTriple a cheese sandwich]]!\\
'''Mercy:''' ''(recovering from injuries in bed)'' Now ''that's'' funny! [[LaughThemselvesSick Ha ha ha... ow!]]
* BadassNormal: Batman as always. When Lex mockingly dismisses Batman as a 'mere mortal in a Halloween costume', a completely serious Joker retorts there's ''nothing'' mere about Batman.
** That said, this aspect of Batman also gets deconstructed during the crossover. Batman's skills and resources give him the edge in Gotham with its street-level maniacs and, for the most part, non-powered super-criminals. But Metropolis ''isn't'' Gotham and its villains are used to dealing with a nigh-invulnerable Kryptonian demigod. So, Bruce's tools become correspondingly, and ironically, ''less'' effective when pitted against someone with access to a similarly advanced -- and ''much'' more lethal -- armory like Luthor's (as the fights with the Wayne/Lex T-7 and the Lexwing demonstrate).
* BatmanGambit: Joker arranges for a beacon to be placed alongside a cruise ship out at sea and emit a distress call. Shortly after Superman gets to the ship, the beacon explodes and causes a hull breach. Superman has to repair the breach and tow the ship back to harbor, forcing Batman to fend for himself against the robot in the meantime. Batman barely lasts long enough for Superman to arrive.
* BigDamnHeroes:
** Batman arrived at the warehouse and was able to destroy the Kryptonite sample to free Superman from his trap.
** When Batman couldn't destroy a robot drone, Superman arrived and crushed it in a single blow.
* BittersweetEnding: Joker and Luthor are stopped and Harley is taken back into custody. Batman and Superman part ways having, despite their initial friction, become FireForgedFriends (thus laying the first foundation of the eventual Justice League). But Lois, having discovered Batman's true identity, has broken up with Bruce. Joker also blew up half of Metropolis before he was stopped (and despite being presumed KIA in the Lexwing's crash, JokerImmunity all but guarantees he somehow survived and ''will'' be back). Luthor likewise escapes any legal culpability for his role in Joker's rampage (though Bruce does at least make the KarmaHoudini financially painful for him by terminating Wayne Enterprises' partnership with [=LexCorp=] ).
* BondOneLiner: As Batman and Harley parachute out of the [=LexWing=] 5000, they realize the Joker is still aboard:
-->'''Harley:''' Puddin'!\\
'''Batman:''' [[DeadpanSnarker At this point, he probably is.]]
* BoundAndGagged:
** Lois is subject to this after being kidnapped by the Joker. At one point, the gag is briefly removed, only for Lois to [[DefiantCaptive immediately start mouthing off at the Joker,]] causing Harley to shove it back in.
** Later on, Mercy gets duct-taped to the side of a KillerRobot so as to prevent Superman from simply punching it to pieces.
* BreakTheHaughty: Superman seems in complete control as he bypasses the Joker's trap. Actually, the Joker's real trap is soon sprung, and he laughs in sadistic glee as he tortures Superman right in front of Lois Lane.
* ButtMonkey: Mercy Graves, Luthor's assistant gets hit with this hard. Harley Quinn [[PunchedAcrossTheRoom punches her across the parking lot]] using her boxing glove gun and she receives an OffhandBackhand from Batman when he interrogates Luthor. She gives as good as she gets when fighting Harley, knocking her out but breaking her arm. Finally, the Joker knocks her out using a KillerYoYo. She gets [[ThrowTheDogABone thrown a bone]] at the end when she gets the satisfaction of seeing Harley locked up and [[LaughThemselvesSick laughs herself sick]] about it, though she still has serious arm injuries.
* CallBack:
** When Luthor suggests the drones be used for military purposes, Bruce declines. Besides his childhood, considering how [[Recap/BatmanTheAnimatedSeriesE59BlindAsABat the last time his company building military weapons went]], who could blame him?
** Back in the [[Recap/SupermanTheAnimatedSeriesS1E1To3TheLastSonOfKrypton Pilot]], Martha Kent had called Batman "that nut in Gotham City". When Batman and Superman finally first meet in this episode, Clark states he'd heard the Dark Knight was crazy.
** Joker going down in flames in the climax whilst laughing all the way echoes his similar death-by-fiery explosion in ''WesternAnimation/BatmanMaskOfThePhantasm''.
* CatFight: Mercy and Harley against each other. It's Mercy who ultimately [[ThrowTheDogABone emerges]] [[LaughThemselvesSick victorious]] in the end.
** The sound mix also plays into the 'CatFight' joke. Sound designer Robert Hargreaves and his team evidently couldn't resisting inserting ThatPoorCat into the final sound mix.
* ChicAndAwe: ComicBook/LoisLane criticizes Bruce Wayne while waiting for him to arrive in Metropolis, and is instantly lovestruck the moment she sees him.
* CombatPragmatist: Batman takes Superman unawares and judo throws him across an alley. Superman responds by getting up and checking Batman across the room, quipping "I heard you were crazy; I didn't think you were stupid". Rather than break out some specialist gadget or use some arcane martial arts technique, Batman holds Superman at bay with some Kryptonite and disappears.
* CompensatingForSomething: Parodied by Joker when he sees Batman's Jet-wing at the end of Part II. He mockingly inquires if Bats, thanks to being around Suprman, is now suffering from "propulsion envy".
* CoolPlane: The [=LexWing=] 5000, a flying wing loosely based on the Northrop YB-49. It's very durable and heavily armed.
* CrazyPrepared: Played both ways when Superman and Joker first confront each other. Sups comes in his lead suit to save Lois, knowing Joker would have kryptonite on him. It seems Joker's plan is foiled ....until he sprays him with acid to dissolve the suit.
* {{Crossover}}: With ''WesternAnimation/BatmanTheAnimatedSeries'', the first of three.
* CrossoverCouple: Bruce Wayne and Lois Lane fall in love. They go so far as to discuss marriage and Lois moving to Gotham City, but when she learns Bruce's SecretIdentity, she decides to stay in Metropolis.
* DamselInDistress: Stop us if you've heard this one before: Lois Lane gets kidnapped to lure Superman into a trap. The twist is that this time, it's the Joker who's behind it.
** This after she was caught in the middle of an attempted hijacking of Air Force One earlier in Part I:
--->'''Superman:''' I hope I didn't shake you and the others up too bad.\\
'''Lois:''' I have to say... I've gotten used to it.
** DamselOutOfDistress: That being said, ''she'' ends up saving ''Batman'' when they're attacked by a KillerRobot. As he's about to be shoved into a printing press, Lois gets the robot's attention by throwing a fire extinguisher at its head, a distraction that Batman takes advantage of to turn the tables... which in turn gives Superman enough time to arrive and finish off the robot.
* DidntThinkThisThrough: Lex agreeing to Joker's proposal to kill Superman with the Kryptonite he's discovered. In his greed and excitement, Lex doesn't stop to consider Joker's infamous reputation and history over in Gotham -- and that, when taking all this into account, means any kind of collaboration with him ''probably'' won't end well. Lex even lampshades to Mercy in Part II -- not that it stops him from trying (and failing) to cut him loose until Part III:
-->'''Luthor:''' What could have ''possessed'' me to trust that clown?!
* DieLaughing: Joker in the climax when he realizes he ain't getting out of this alive. As the Lexwing goes down in flames, he laughs his ass off in the face of death (although it's ultimately a subversion since, obviously, [[JokerImmunity it won't stick for long]] and Joker would be back [[Recap/TheNewBatmanAdventuresE7JokersMillions a month later]] no worse for wear).
* DiegeticSoundtrackUsage: The Jack in the Box that Harley uses in the opening plays the Joker theme.
* DoNotGoGentle: Harley in the epilogue. Turpin and Sawyer have to all but forcibly shove her into the prisoner transport back to Arkham when Harley refuses to cooperate and won't shut up.
* DoesntLikeGuns: Bruce as always, which is why he blocks Lex from marketing the Wayne Enterprises-[=LexCorp=] robots to the American military in Part I.
* DrivesLikeCrazy: Harley behind the wheels of Luthor's limousine in Part I goes ''exactly'' how you'd expect.
* DynamicEntry: When Lex Luthor and The Joker are in a scuffle, Harley Quinn's intervention is interrupted by a flying kick courtesy of Mercy.
* EvenEvilHasStandards:
** After the Joker muscles into Caesar's gang, one of the mooks (Binko) [[ScrewThisImOuttaHere leaves and refuses to go back]]. He's a criminal, but he doesn't want anything to do with Joker. It's also further justified, because Batman's dialogue while interrogating him establishes Binko used to operate out of Gotham City before relocating to Metropolis. So unlike Carlini and the other Metropolis mobsters, a former Gothamite like Binko knows ''exactly'' what having Joker in town (let alone working for him) means and how it ''won't'' end well.
** When the Lex-Wing begins its attack on Metropolis in the climax of Part III, you can see even Harley looks shaken at the sheer scale and destruction of Joker's latest rampage.
* EvilIsNotAToy: Like [[WesternAnimation/BatmanMaskOfThePhantasm Salvatore Valestra]] before him, Luthor finds this out the hard way about working with the Joker.
* ExplainExplainOhCrap: The hijackers when they realise that Lois Lane is onboard; that same woman that Superman is always turning up to rescue...
* ExplosiveDecompression: Weaponized; Superman rips a hatch off Air Force One to enter. The terrorists are blown towards the door by the escaping air (while the hostages have been strapped to their seats) and right into Superman's fist. It's not revealed how he sealed the hole afterwards, but he ''is'' Superman:
-->'''Lois:''' [[DeadpanSnarker Thanks for strapping me in.]]
* FaceDeathWithDignity: When Joker sees the explosive marbles heading his way as the [=LexWing=] goes down, he naturally laughs himself silly before the plane explodes. Course Joker [[JokerImmunity being Joker]], it naturally won't hold for long.
* FailedASpotCheck: In Part III's battle with the robots, neither Bruce or Clark notice something: there's no sign of Joker's remaining Kryptonite. Clark finds out the hard way where it is moments later when the final robot attacks.
** Joker and Harley somehow failed to notice Batman made it into the Lexwing cockpit until he was trying to pull the Clown off the control yoke.
* FatalFlaw: Joker's pride (and not for the first time in the DCAU). His massive egotism and pathological need for showmanship, more than anything, is what ultimately brings down the Plan.
* FireForgedFriends: Superman and Batman starts off not on good terms and mistrusting each other, but by the end they recognize their effectiveness as a team and their relationship becomes one of respect and trust (well, trust on Superman's side, anyway).
* {{Foreshadowing}}:
** A probably unintentional one, but it's mentioned that previous owners of the Laughing Dragon all met early demises due to the fact it was made of kryptonite and the radiation coming from it. [[Recap/JusticeLeagueS1E8And9InjusticeForAll Years later]] in ''WesternAnimation/JusticeLeague'' we find out Luthor held a small piece of kryptonite for years to keep Superman at bay and caught a terminal illness from it. (Then again, the latter was a plotline that had already played out in the comics...)
** In Part I, Joker states that he's read up on Superman to learn his weaknesses. This pays off in the next episode, as Joker knows all about the anti-Kryptonite lead suit S.T.A.R. Labs built for Superman. He correctly anticipates Big Blue will bring it and prepares accordingly to counter it with his acid.
** In Part III, Superman notes Luthor's been lining his buildings with lead to block his X-Ray vision (which is also one of the reasons why he's had trouble finding Lex and had to team up with Batman). The lead-lining ends up being crucial to winning Superman's fight with the final robot (and its Kryptonite).
* FramingTheGuiltyParty: Attempted by Luthor and Mercy in Part III after the Wayne/Lex T-7 fails to kill Batman. With the robot now in police custody, Luthor and Mercy both know it won't take long before the cops (or the heroes) trace it back to [=LexCorp=]. To get ahead of this inevitable exposure, Lex arranges a final meeting with Joker and Harley at the research facility to ostensibly to plan their endgame...[[YouHaveOutlivedYourUsefulness only to betray them]]. The story Luthor and Mercy intend to sell to the authorities is that Lex personally investigated the robot's "theft" and "discovered" Joker and Harley's presence at the scene of the crime. [[HeKnowsTooMuch To ensure Joker and Harley can't contradict this testimony]], Mercy will also execute them (and presumably sell their deaths as the Gotham criminals being regretfully "shot while resisting arrest"). Luthor will thus have a plausible cover story, witnesses silenced, ''and'' the remaining Kryptonite in his possession. Unfortunately for Team Lex, [[ProperlyParanoid Joker saw the betrayal coming.]]
* FunnyBackgroundEvent: Luthor and Joker meet each other face to face and sic their henchgirls against each other (Mercy and Harley of course). They eventually get to calmly talking while the girls brawl in the background.
* GenreBlindness: Joker is genuinely surprised that Batman would follow him all the way to Metropolis.
* HeadbuttingHeroes: Between Batman's poor people skills and Superman's irritation with him (both for their different styles and Bruce's relationship with Lois), there's plenty of this until the two reach an understanding and formally team up against their common foes.
* HitchhikersLeg: {{Gender Flip}}ped when The Joker pulls this on ''Harley'' (who is kidnapping Lex, sorta):
-->'''Harley:''' Whoa, mama! Check out the cute hitchhiker!\\
'''Joker:''' Yoo-hoo!
* HoistByHisOwnPetard: The Joker's explosive marbles make a handy distraction when Batman and Superman escape his warehouse trap and corner him, but they spill out of his bag when he's trying to flee the [=LexWing=] 5000. The explosions prevent him fleeing the ship, and he's trapped as the ship sinks into the ocean.
* HollywoodAcid:
** {{Averted|Trope}}; Batman notes the hydrochloric acid would take weeks to melt down the wall of the room he and Superman are trapped in. Played straight when Superman suggests Batman melt the kryptonite instead, and it works almost immediately, although what the acid did was denature the kryptonite.
** Played straight with Joker's acid flower as it immediately burns through Superman's anti-Kryptonite lead suit.
* HumanShield: The Joker leaves Mercy bound to the side of one of the robots, which turns to interpose her between itself and Superman so he can't just punch it.
* IKnowYoureWatchingMe: After Superman uses his X-Ray vision to find out that Batman is Bruce Wayne, Batman puts a tracker on Superman. When Superman returns home and finds it on his cape, he looks out the window to see Batman looking at him via binoculars. Batman simply waves to him and leaves having found out Clark's secret identity as payback.
* IfYouEverDoAnythingToHurtHer: When Bruce Wayne leaves for Gotham again, he tells Clark that "[Lois] is all yours, if you can handle her. But you better be good to her, [Batman voice] 'cause I know where you live."
* ImperialStormtrooperMarksmanshipAcademy: Bruce Wayne gets surrounded by a gang, at point-blank range, with no cover. Somehow, they all managed to miss, and Bruce falls off the high-floor restaurant he was in. When Bruce does land, he is immobilized and the gang ''still'' can't hit him.
* IncrediblyObviousBug: Batman plants a dime-sized ''flashing'' bug on Superman. Superman can't even find the bug until after he's changed into Clark Kent and Batman's figured out his identity. It's arguably justifiable, as the thing ''was'' hidden in the folds of his cape, and Clark was too distracted to pick up on it earlier; Bats made sure to piss Superman off before he planted it, thus ensuring the Man of Steel wasn't thinking clearly on his way home, plus he was grappling with the discovery of Batman's true identity and that the Joker is both in town and has access to Kryptonite.
* InvisiblePresident: The President is never shown or heard; the closest we get is Superman talking to him through the window of his limo.
* JokerImmunity: As with practically every near-death, Joker somehow manages to survive plummeting to the ground in an exploding airplane with grenades going off right in his face (though this is at least not confirmed until after the special).
* KarmaHoudini: As expected, Lex is ultimately able to escape any legal consequences for his role in Joker's rampage. However, Bruce at least is able to use the incident to publicly sever Wayne Enterprises' partnership with [=LexCorp=].
* LaughThemselvesSick: Mercy laughs hard at a news report of Harley being sent back to Arkham (hysterically ranting and raving as she is), then winces as the motion aggravates her injuries.
* {{Leitmotif}}: As the first official crossover between BTAS and STAS, episode composer [=Michael McCuistion=] brings back Shirley Walker's iconic Batman theme.
** In contrast, Walker's Joker leitmotif only briefly reappears. In the La La Land Records STAS Collection's linear notes, [=Michael McCuistion=] states he was given leeway to compose a new Joker theme (which only appears in these episodes). Walker's Luthor leitmotif was likewise replaced with a new theme created just for these episodes. The Bruce/Lois romance also receives its own letimotif.
* LikesClarkKentHatesSuperman: Lois falls in love with Bruce Wayne, but greatly dislikes Batman. She was upset to find out they're one and the same. As a result, Lois breaks up with him. Between that, and before their last confrontation with Joker and Luthor, Bruce inverts and lampshades this with Clark:
-->'''Batman:''' It's ironic, you know. She likes Bruce Wayne and she likes Superman. It's the other two guys she's not crazy about.\\
'''Superman:''' Too bad we can't mix-and-match.
* LoopholeAbuse: Lex says it doesn't take much "imagination" to market the Wayne Enterprises-[=LexCorp=] robots to the American military in Part I. Bruce, however, points out to Lex that the agreement between their two companies specifies that "any technological applications of the project need ''his'' approval first". And since Bruce doesn't like guns... well...
-->'''Bruce:''' Blame it on me, Lex. Tell your pals at the Pentagon I just don't have the imagination.
* MacrossMissileMassacre: How the Lexwing takes down the Batwing during Part III's Final Battle.
* MadeForTVMovie: This episode is 3-parts long and was originally premiered as one of these. It's been repackaged as a single movie, filled with obvious pauses for commercial breaks. You can get it on DVD however without the breaks.
* MakeSureHesDead: After Bruce falls from the high-floor restaurant, the Joker, knowing that "in this town some flying fool could've caught him", orders the men to make sure he's actually dead.
* [[MrExposition Ms. Exposition]]: Following the capture of Harley Quinn, Angela Chen delivers the following news-report the day after:
-->'''Angela Chen:''' Hello, this is Angela Chen. ''[Scene changes to aerial view of Lex-Wing wreckage]'' Though the search for Joker's body continues the Coast Guard reports it is extremely unlikely that Gotham 's most notorious criminal survived the crash. ''[Scene changes to Luthor walking stoically by a mob of reporters]'' In related news, billionaire Lex Luthor was again rigorously grilled by the DA 's office over his alleged connection to The Joker's rampage. His statements have been questioned both by local law officials, and industrialist Bruce Wayne who announced the immediate termination of his partnership with Lexcorp. ''[Scene changes to Maggie Sawyer and Dan Turpin holding Quinn in a straight jacket]'' And on a lighter note Joker accomplice Harley Quinn was returned to Arkham Asylum for another round of rehabilitation.\\
'''Harley Quinn:''' I want a lawyer. I want a doctor. I want a cheese sandwich! ''[Sawyer and Turpin throw Quinn into a paddy wagon that drives her away]''\\
'''Mercy:''' ''[Watching [=TV=] while bandaged] ''Now that's funny!''Hahaha--'' Ouch!
* MysticalJade: In this crossover special, the Joker steals a valuable jade Dragon from a pawnshop, said to carry a curse that kills its owners. Subverted in the fact that the "jade" is actually kryptonite and it was the low level radiation it emits that was killing its owners.
* MythologyGag:
** The crossover's title is an homage to ''[[ComicBook/WorldsFinest1941 World's Finest]]'', which was published between 1941 and 1986. The book was best known for teaming up Superman and Batman in most issues.
** When Superman smashes through the roof the Joker snarks, [[Series/TheAdventuresOfSuperman "More powerful than a locomotive]]...and just about as subtle!"
* NeverFoundTheBody: The Joker is left for dead in a falling airplane; with explosions going on all around him, Joker simply laughs as the aircraft plummets into the water. A news reporter says that it is unlikely that Joker survived.... yeah right. (Curiously, this was one time even Batman seemed to have doubts whether he had survived. When Harley - whom Batman had managed to rescue - shouted, "Puddin'!" in anguish, he replied, "At this point, he probably is.") Joker is later confirmed to have somehow survived thanks to his continued appearances in ''[[WesternAnimation/BatmanTheAnimatedSeries The New Batman Adventures]]'', ''WesternAnimation/JusticeLeague'', and flashbacks in ''WesternAnimation/BatmanBeyondReturnOfTheJoker''.
* NeverMyFault: During their 'negotiation' in Part II, Lex is surprised and furious that Batman followed Joker to Metropolis. Joker flippantly absolves himself of any responsibility for Batman's pursuit -- even though his public robbery of the Gotham Antique Store in Part I was what got Batman's attention in the first place.
* NiceJobFixingItVillain:
** In Part I, Joker gasses the Antique Shop owner to steal the Laughing Dragon. If he had just robbed the store anonymously, Gordon, Bullock, and even Batman would likely have written it off as your average run-of-the-mill robbery. By robbing the store so publicly, it gets everybody’s attention and Bruce personally investigates to determine ''why'' Joker would be so interested in an antique jade statue. Joker also foolishly left the statue's base behind, which contained several fragments of chipped off Kryptonite. If he'd just taken it with it, Bruce wouldn't have been able to examine one of the fragments and wouldn't have deduced where Joker was headed next.
** Later in Part I, Joker makes the same mistake when he deposes Metropolis Mob Boss Caesar Carlini and seizes control of his men and operations. Such a move would send ripples through the local underworld and attract the attention of Turpin and the Metropolis PD regardless. But the way Joker disposes of Carlini (dosing him with Joker toxin) instantly alerts the Inspector and Superman just who's come to town.
** In Part II, after the lab's destruction and the ensuing damage control press conference, Lex angrily vents to Mercy that he has no idea what possessed him to place his faith in 'that clown'. Unknown to either of them, Superman is present as Clark Kent and picks up on their conversation with his super hearing. This allows Clark to realize that Joker isn't working alone and grudgingly passes on the intel to Bruce (who proceeds to interrogate Luthor as Batman).
** In Part III, Superman struggles against the big robot, due to the kryptonite, but then it picks up the factory's door:
--->'''Superman:''' Lead-lined door. I'll have to thank Luthor.
* NoOneCouldSurviveThat: After the big crash, the Coast Guard reports [[NeverFoundTheBody they can't find the Joker's remains]], but they openly doubt he could've survived.
* NoodleIncident: From Batman's dialogue while interrogating Binko in Part I, the mobster is a former Gothamite who had at least one run-un with the Dark Knight before relocating to Metropolis.
* NotSoDifferentRemark: Joker does this as part of his sales pitch to Lex in Part I. Lex clearly dislikes the comparison:
-->'''Joker:''' I sense we are kindred spirits, you and I. Oh, there are differences, to be sure, like hair. Heh heh! But underneath it all, we're both entrepreneurs, men of vision. We see an opportunity, we grab it. Am I right?
* NotSoStoic:
** Even Lex lets out a look of total horror (see OhCrap below) when he realizes that Joker plans to blow up half of Metropolis using his own weapons.
** The usually stoic and professional Mercy Graves not only lets her anger out when dealing with Harley Quinn, but is last seen [[ActuallyPrettyFunny laughing her butt off as she watches Harley's arrest on TV.]]
* NotTheFallThatKillsYou: After falling out of a high rise restaurant, Bruce falls several stories before catching himself on a windowsill several stories down. That kind of sudden stopping force should have destroyed the windowsill or his shoulders.
* OffscreenVillainDarkMatter: While this story is well-known for subverting this in regards to the Joker's usual funds (hence his trying to do a straightforward hit-job), it also plays it straight, in a way. Even supposedly broke, the Joker somehow has enough intel to track down a giant chunk of Kryptonite that nobody else, not even Lex Luthor, has ever heard of.
* OhCrap:
** One of the most memorable OhCrap moments in the entire Animated Universe:
--->'''Mercy:''' Joker took [Luthor] in the [=Lexwing=]! He said he'd make him lose everything he ever built!\\
'''Superman:''' ...Luthor's built half of Metropolis.
** An earlier one happens in Part One, when terrorists hijacking Air Force One learn that [[AlwaysSaveTheGirl Lois Lane]] is on board:
--->'''Terrorist:''' Let's make an example of this hero. A very tragic example, I'm afraid, Miss...?\\
'''Lois:''' Lane.\\
'''Terrorist:''' Lane? Lois Lane? The one Superman always saves?!\\
'''Lois:''' 'Fraid so.\\
''(cue Superman's arrival)''
* OhCrapFakeout: When Superman shows up in a lead suit to counter the Kryptonite the Joker brought, the latter goes into [[https://www.youtube.com/watch?v=NYdIYtMGSQw a melodramatic "Woe is me" rant]] before snapping his fingers and chuckling, "Oh, silly me! I forgot the acid!" and melts his suit.
* OOCIsSeriousBusiness: A plot point in Part I. Batman's shut down Joker's Gotham operations and he's desperate for cash. Robbing an antique store thus makes sense... and yet he ''only'' steals a single antique statue rather than loot the entire inventory. This immediately triggers Batman's suspicions and an analysis of the remaining statue fragments allows him to discover it was Kryptonite (and thus deduce Joker's headed for Metropolis).
* OutsideContextProblem: Superman and Batman's arch enemies prove to be more than either one of them can handle when they swap partners. Superman greatly underestimates the Joker's intelligence, allowing the clown to easily get the drop on him. Meanwhile, Batman is no match for Luthor's technology, and can only stall for time against his killer robot until Superman arrives.
* PowerCreepPowerSeep: Mostly averted. The Joker sets up a kryptonite-filled death trap for Supes and Batman has to race over there to rescue him. Later, Lex Luthor sends a KillerRobot after Bats and all he can do is stall for time until Superman stomps it. Generally Superman used more brute strength while Batman used tactics and gadgets to survive.
** The killer robot was also given a realistic way to stand up to Superman: Harley Quinn had gagged and duct-taped Mercy to the robot, making it impossible for Superman to hit it without killing her too.
* PowerCopying: Joker accuses Batman of this flying like Superman, calling him a "Copy-bat!"
* ProperlyParanoid: Luthor's attempt at FramingTheGuiltyParty in Part III fails because he underestimates Joker's intelligence. The Clown correctly anticipated Lex was gonna try to screw him (and Harley) over and came prepared for the betrayal.
* RecognitionFailure: Bibbo Bibbowsky has no idea who The Joker is.
* RememberTheNewGuy: Caesar Carlini is a prominent Metropolis mobster, yet he's never been mentioned before this episode. Similarly, Binko is a former Gotham mobster who's had at least one run-in with Batman before, yet he's likewise never been mentioned over on BTAS.
* SaveTheVillain: Played with in the climax. Bruce and Clark ''do'' rescue Harley and Luthor before the Lexwing goes down...but neither hero particularly has any problem leaving The Joker behind to an almost certain death. Even Alfred looks pleased to hear that The Joker might have perished in the Lexwing the next day.
* SavedByThePlatformBelow: The Joker and his thugs cause Bruce Wayne to topple from the terrace of a penthouse nightclub. "See that he's street pizza. In this town some flying fool [[CatchAFallingStar could have caught him]]!" the Joker orders, whereupon the {{mooks}} find Wayne alive and intact on a window washers' gantry several stories below the roof. Intersects with DeusExMachina that such a gantry would be deployed there, at night, with no workers in sight.
* TheScapegoat: After exposure of Lex's connection to Joker becomes inevitable in Part III, Lex and Mercy try to throw Joker and Harley under the bus. Unfortunately for them, Joker saw the betrayal coming.
* ScrewTheMoneyIHaveRules: Lex says the Joint Chiefs are interested in the robots, and he sees quite a lucrative opportunity there. Bruce will have none of that, however, and notes the contract grants him the authority to tank such a proposal no matter what Lex says:
-->'''Bruce:''' I don't like guns.
* ScrewThisImOuttaHere:
** This is the catalyst for the crossover. With all their local operations shut down by Batman and their finances strained to the breaking point, Joker and Harley flee Gotham for Metropolis.
** After Batman and Superman save Mercy from one of the reprogrammed robots, they are immediately attacked by an even bigger, tougher robot. While the two decide what to do next, Mercy can be seen slowly inching away - and she bolts for her life once they break into action.
** Bruce Wayne and Wayne Enterprises publicly do this following Joker's defeat. In response to the allegations of Lex's connection to Joker's rampage, Bruce immediately terminates his company's partnership with [=LexCorp=]. Privately, of course, Bruce knows damm well Lex ''is'' guilty -- and even if Lex escapes legal consequences (which he does), at least Bruce can ensure that escape is financially costly for the Metropolis magnate.
* SecretKeeper: Lois, of all people, learns Bruce is Batman. Their relationship falters because Lois realizes Bruce is MarriedToTheJob. She's spent enough time with a superhero to know that Bruce isn't retiring anytime soon. Perhaps just as serious, she, as a reporter, just can't make this juicy bombshell public.
* SharedFateUltimatum: After Batman fires missiles from the Batwing at the Lex-Wing:
-->'''Joker:''' Batman! It's always Batman. What do you got in the way of air-to-air missiles, Lex?\\
'''Luthor:''' You're asking ''me'' for help?\\
'''Joker:''' ♫ If I go down, you go down ♪\\
'''Luthor:''' It's a red switch.\\
'''Joker:''' ''[[[NeedleInAStackOfNeedles Sees console full of red buttons]]]'' Which red--? Oh, the heck with it. ''[presses several buttons [[MacrossMissileMassacre which launch missiles]], with one disabling the Batwing].''
* ShoutOut:
** The Joker remarks on the [[Creator/RicardoMontalban "rich Corinthian leather"]] seats of Luthor's limo.
** A reference to an advertising mascot combined with a joke about Luthor's {{bald|OfEvil}}ness:
--->'''Luthor:''' You know I can't be connected to this in any way.\\
'''Joker:''' Oh, you'll be [[ProductAsSuperhero Mr. Clean]]!
* SpannerInTheWorks:
** Batman ends up being this to Joker's deal with Lex. Neither he or Harley anticipated the Dark Knight would leave Gotham to pursue them all the way to Metropolis.
** Batman's interrogation of Luthor in Part II. Within less than a minute of "chatting" with Lex, the proud, arrogant business mogul is left off-balance and visibly terrified of the Dark Knight. With Lex already halfway on the ropes, Bruce might very well have been able to extract a confession then and there. Unfortunately, the interrogation is interrupted by Lex's other bodyguards trying to break into his bedroom. Bruce has to leave Luthor with only a warning and a promise of a follow-up (which quickly backfires, as Luthor immediately agrees to Joker's revised terms and gives the Clown the Wayne/Lex T-7 to deploy against Batman).
* SpiderTank: Wayne Company and [=LexCorp=] have been working together on a spider/insect like robot named the Wayne/Lex T-7, initially for space exploration purposes. However Lex Luthor found military uses for it, despite Bruce Wayne's objections, and had some of them equipped with gattling guns and laser weapons, including a giant dark-grey variant. The Joker uses them against Batman and Superman.
* SquirtingFlowerGag: Joker uses his squirting flower to dose Superman with acid, destroying his kryptonite proof suit.
* TheStoic:
** Bats, for the most part. When Supes uses X-Ray vision to see Batman's identity:
--->'''Superman:''' Bruce Wayne?!\\
'''Batman:''' You peeked.
** The Joker, to a degree. His reaction to Lex Luthor machine gunning his hideout when he failed to kill Superman is a mild "how did I know Batman would show up?"
* SuperPersistentPredator: The Wayne/Lex T-7 unleashed by the Joker on Batman. It's too strong, tough and well-armed for Batman to face it in a fight even with his cunning and arsenal; and too smart, fast and agile for Batman to lose it. It takes Superman's intervention to finally get rid of it.
* TemptingFate:
** Luthor spends Parts I and II dismissing Batman as "a mere mortal in a Halloween costume" and "a mental case in a fright mask". Naturally, the Batman inevitably stops by to "call" on Lex (leaving Luthor visibly off-balance and terrified by the Dark Knight).
** Faced with the big robot, Superman tells Batman to go after the Lexwing and says this won't take long. Then he finds the robot has the rest of the kryptonite taped to it.
** A more lighthearted instance when Clark exchanges farewells with Bruce at the Metropolis Airport. In spite of their earlier friction, Clark now feels they actually worked pretty well together -- not that he'd want to make it a regular event. Not only will Clark and Bruce [[Recap/SupermanTheAnimatedSeriesS3E2KnightTime team up]] [[Recap/SupermanTheAnimatedSeriesS3E11TheDemonReborn twice more]] before the end of STAS, but both men will eventually go on to co-found the Justice League and work together on a weekly basis.
* ThisIsGonnaSuck: Superman is not pleased to note how Caesar Carlini's nonstop laughing tells them which notorious criminal has come to town.
* {{Touche}}: Clark mutters this when he finds a tracker on him and uses his super-vision to see Batman is spying on him to discover his secret identity, in retaliation for Superman finding out his during the fight at the club.
* UnderestimatingBadassery:
** {{Ba|dassNormal}}tman and [[PowerBornOfMadness the Joker]] are both seen as mere mortals against virtual gods like Superman and Lex Luthor. When Luthor laughs at him for thinking he can kill Superman despite being unable to defeat "a mere mortal in a Halloween costume" like Batman, the Joker [[BerserkButton gets deadly serious and grabs Luthor by the collar]]:
--->'''The Joker:''' There's nothing ''mere'' about ''that'' mortal.
** Superman finds this out when he tries to interrupt Batman's interrogation, only to get judo-thrown across the room (and has to take a moment to get over the surprise). And ''then'' Bruce brings out the tiny shard of kryptonite...
** Batman winds up scaring Luthor by breaking into his penthouse in the middle of the night and interrogating him. Luthor immediately contacts the Joker and agrees to pay what he's asking.
** Batman does this to Luthor, intimidating him in his own bedroom and treating him like he would any normal criminal that he would be able to terrify into submission. He seemed to overlook the fact that Luthor is the head of a massive corporation, with resources that are able to challenge *Superman* himself. Resources like a killer robot that Batman is barely able to hold off, and required Superman's intervention in order to put down for good.
** Naturally, The Joker soon proves he's much, much more dangerous than you'd ever think a clown to be. Superman thinks he's got him beat by showing up in a lead suit, but Joker has other tricks up his sleeve... and on his lapel. And Luthor is horrified to find out Joker's just as much a threat to him and every single person in Metropolis as he is to the heroes:
--->'''Batman:''' Expect the unexpected.
* TheUnmasking:
** Superman unmasks Batman during a confrontation in a nightclub by using his x-ray vision to peek beneath the mask.
** During the confrontation, Batman slipped a small tracker on Superman and followed him back to his apartment and saw he is Clark Kent.
** Lois Lane discovers Batman's identity when he loses his cape and cowl during a fight against a robot. As Lois has romantic feelings for Bruce, she cannot bring herself to reveal she knows Batman's identity to the world. That said, she cannot be with him as she won't stay home and fear for his safety knowing what he is doing on the streets.
* VictoriousLoser: Mercy has clearly sustained more injury from fighting Harley than Harley did from fighting her, but at the end of the henchwomens' conflict, Mercy is the one laughing last while Harley is hauled back to Arkham.
* VillainTeamUp: Luthor and the Joker.
* WhamEpisode: One of the biggest in the entire DC Animated Universe. After the setup back in the Pilot (i.e. Martha Kent's line of "That nut in Gotham City"), it's finally and explicitly confirmed that BTAS and STAS [[SharedUniverse share the same continuity]]. This episode in a sense is the true beginning of the DCAU and, while unplanned, really begins the march towards ''Justice League''.
* WhamLine: "This so-called 'jade' is emitting low-level radiation."
** This line winds up being even ''more'' impactful come Justice League.
* WhatDoesThisButtonDo: The Joker asks Lex Luthor how to operate the weapons on the [=LexWing=], but Luthor is uncooperative. Joker responds by hitting as many buttons as possible.
* WouldHitAGirl: Bats KO's Mercy when she pulls a gun on him.
* YiddishAsASecondLanguage: Harley tells the store manager he'll "plotz".
* YouDidntAsk: Lois accuses Bruce of lying for not telling her he was Batman. Bruce responds cheekily, "Now, I never actually said I ''wasn't'' Batman." Lois responds by {{Dope Slap}}ping him on the back, directly on the iodine-soaked wound.
* YouHaveOutlivedYourUsefulness: After two failures, Lex has had enough of The Joker. Unfortunately for Lex, [[ProperlyParanoid Joker saw it coming]].
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