It's an average day in Metropolis: Franchise/{{Superman}} breaks out of [[BedlamHouse Arkham]] [[CardboardPrison Asylum]], overseen by Solomon Grundy, LoisLane is [[SelfDemonstrating/LexLuthor the richest, vilest, and]] [[BaldWoman baldest woman]] in (and owner of) the city, and Bizarro #1 is the most beloved (and destructive) hero in the city.

...sorry, what?

Well, it turns out that this is what happens when [[GreatGazoo Mr. Mxyzptlk]] accidentally gives most of his power to SelfDemonstrating/TheJoker, who creates a mind-bendingly odd world for giggles so that he will be able to kill Batman over and over and over again. Of course, in doing so he's risking tearing the fabric of reality apart at the seams, but when has he ever worried about that?

What started out as a mind-boggling inversion of everything Superman knows to be true turns into a race against time to stop the Joker's reality warping and get the associated powers back to their rightful owner.
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!!This comic book miniseries contains examples of:
* AdaptationDistillation: ''WesternAnimation/BatmanTheBraveAndTheBold'' loosely adapted this storyline in one episode, with Batman instead of Superman defeating The Joker (and Bat-Mite instead of Mxy). And the many deaths of Batman at the hands of the Joker became less graphic and more comical, off-screen, and LighterAndSofter, but still disturbing for children (in Batman's first death, they even showed him as a [[WingedSoulFliesOffAtDeath winged angel playing a harp and flying off to heaven]]... for a short while anyway).
* AndShowItToYou: The Joker does this to Superman near the end. Superman survives for several minutes afterwards.
* BreakingTheFourthWall: The Joker, even going so far as to turn the page for the reader.
* BreakTheBadass: At the end, after Joker's beaten, [[spoiler: Batman's seen huddling and weeping in horror. Superman is forced to take his memories of Joker's atrocities to heal him.]]
* BurgerFool: ComicBook/{{Superboy}} works at one of these under Joker's reign.
* ButForMeItWasTuesday: Satanus is completely unfazed with The Joker's take on him, chiefly because of the IHaveManyNames nature of him. He also proves that he can step away from the Joker's incarnation of him very easily.
* CallBack: The story recalls the first ''Franchise/{{Batman}}''/''[[ComicBook/IncredibleHulk Hulk]]'' CrossOver, when The Shaper of Worlds gave SelfDemonstrating/TheJoker reality-warping powers. That story ended with Batman TalkingTheMonsterToDeath just as Superman did in this story.
* CardboardPrison: The Joker is ultimately sent to a real prison called Slabside Penitentiary, which takes pride in the fact the no one has ever escaped from it. [[StatusQuoIsGod This didn't last]] as during ''Joker: Last Laugh'', after being lied to and told he has terminal cancer, the Joker engineers and pulls off a jailbreak, and subsequent stories would see Joker back in Arkham.
* {{Cloudcuckooland}}
* {{Determinator}}: Superman offers to take Batman's memories of being horribly killed over and over and over in order to mend his (Batman's) utterly shattered mind. Superman was also the only being who never gave up under Joker's reign.
* DidYouJustScamCthulhu: Mxy decides to give the Joker just 1% of his power to see what he will do with it. The Joker scams him into handing over 99%.
* EnemyMine: {{Darkseid}} of all people tries to do this with the council known as the Quintessence, which contains his mortal enemy Highfather, because The Joker could potentially gain the Anti-Life Equation with his powers, but The Joker warped them, too.
* EndOfTheWorldSpecial: [[spoiler: At the end, the Joker destroys the universe. Mxy supervises its rebuilding.]]
* EvenEvilHasStandards: The Joker will kill Batman and everyone associated with Batman, repeatedly, with creative and horrible ways. He will eat everyone in China. He plans to destroy the universe. He will ''not'' kill Superman after he's been turned into a dog, simply because killing a dumb animal isn't funny.
* FateWorseThanDeath: Satanus invokes the trope as he kicks Superboy and Supergirl out of Hell after they've been killed - after offering a standard DealWithTheDevil, he gets annoyed with Supergirl's incessant prayer and sends them back to the Joker's world, commenting there weren't many Hells worse than ''that''.
* FourthWallObserver: The Joker, even more so than usual.
* GodEmperor[=/=]MadGod[=/=]WorldGoneMad: The Joker + Reality warping powers = this.
* {{Gonk}}: Gorgeous Gilly is ugly as sin, but uses her powers to make men fall in love with her.
* GutPunch: Superman first assumes (when he finally realizes that this isn't right) that Mxyzptlk is responsible for all the changes. Standing on the Moon, he received a truly epic gut punch when he looks back at the Earth and sees its a cube with the Joker's face as the landmass on each side.
* IKnowYourTrueName: The Joker uses this knowledge to steal Mxy's power.
* ImAHumanitarian: When the Joker decides to have Chinese for lunch, he decides to have all billion or so of them.
* ImpossiblyLowNeckline: Harley looks like she's on the verge of popping out of several outfits in the first half.
* JustToyingWithThem: The Joker can't ''not'' toy with Batman.
* LaserGuidedKarma: Joker's fate.
* LateArrivalSpoiler: If you bought the original monthly issues, then who exactly was responsible for this was kept secret until TheReveal halfway through, with the title of the arc being given as "Superman: Arkham!" The ''Emperor Joker'' oneshot at the halfway point was solicited as ''Emperor ?????''. If you buy the trade, of course, it says ''Emperor Joker'' on the cover.
* LogicBomb: Leads to the Joker's defeat. [[spoiler: How can he be all powerful if he can't just kill Batman once and for all?]]
* MagicKiss: The Joker has one. When Harley Quinn thinks she's about to die after all she's done for him, he says, "You ''kooky'' kid -- c'mere," and as they both kiss, his is a powerful one that turns her into a constellation. So heartwarming.
* NotSoOmniscientCouncilOfBickering: Darkseid is aware of the Joker's ascension and the peril it places reality in (and how the lunatic has access to the Anti-Life Equation), so he contacts the Quintessence, a group of cosmic entities devoted to the good of the universe - to convince them not to bother him while he deals with the situation. Unfortunately, by the time he's presented his case, the Quintessence has already been reduced to imbeciles by the Joker.
* OmnicidalManiac: The Joker is prepared to unmake all reality simply because it created ''him''.
* OnlySaneMan: Aside from the heroes, Joker left a single person untouched and drew him into his demented world - SelfDemonstrating/LexLuthor. He was not pleased. Not pleased ''at all''.
* RealityBleed: Small hints of standard reality leak through the Joker's rewoven fabric of the universe, offering the heroes hints that something--okay, ''everything'' isn't right.
* RealityWarper: As annoying as Mr. Mxyzptlk is, the Joker with his power is ''worse''.
* RealityWarpingIsNotAToy
* RushmoreRefacement: The Joker remakes the whole world in his image.
* SdrawkcabAlias: "[[MadnessMantra Rekoj Rorepme... Rekoj Rorepme... Rekoj Rorepme...]]"
* ShootingSuperman: To Batman's credit, in involves missiles.
* ShoutOut:
** The Joker's revamp of the MartianManhunter is pretty much [[WesternAnimation/LooneyTunes Marvin the Martian]].
* SuperEmpowering: To the Joker.
* VictoryIsBoring: The Joker literally cannot bring himself to kill Batman once and for all, because he defines himself with Batman as his foil.
* VillainousBreakdown: The Joker, when he realizes that he literally can't exist without Batman.
* VillainWorld
* WhamEpisode
* WipeThatSmileOffYourFace: The Joker removes Batman's mouth. Batman communicates using Morse code and by clicking his teeth. Because he's Batman, dammit.
* WoobieDestroyerOfWorlds: The Joker skates close to this, deciding that any world where someone like him could happen simply shouldn't exist.
* WorldShapes: In this case, a cube, with landmasses on each face shaped like the Joker's visage.
* WriterOnBoard: Possibly a few early gags poking fun at organized religion were inspired by Jeph Loeb's own viewpoints.
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