Usually, "if you can't beat 'em, join 'em" is standard... but what if you could make ''them'' join ''you?'' This is what a lot of SaturdayMorningCartoon villains have thought, anyway, and use a spell, artifact or machine that can invert the target's morality like a mirror. The hero subject to the Mirror Morality Machine will suffer an instant FaceHeelTurn and go over to the bad guy's side. The CharacterAlignment of the hero will go from Good to Evil and Lawful to Chaotic. Alternately, it may simply "suppress" his conscience and give his ego free rein to do whatever mischief he wants. Usually this results in [[PokeThePoodle cheeky but harmless]] [[MaddenIntoMisanthropy misanthropic antics]], despite the villain's darker intentions.

Usually the effects of the machine will have a time limit, after which its effects will wear off and the hero has to [[ClearMyName clear his name]] for all the things he's done. However, his SideKick will usually stop him before he does anything ''really'' bad and reverse the effects... or the bad guy will do it voluntarily because [[PityTheKidnapper the hero is a better villain than he is]]! This applies when the machine is not an InstantAllegianceArtifact, and the hero-turned-villain [[TheStarscream turns on his "boss"]].

Of course, this being a morality-reversing ray, if the hero turns it on the villain, the villain will spend the rest of the episode as a contrite, cheerful and helpful soul. Sadly, ItOnlyWorksOnce and the heroes [[BrainwashingForTheGreaterGood can't keep dosing the bad guy]], something about it being "[[PygmalionSnapback immoral]]" or something. [[HeelFaceMindScrew Most of the time]].

The artifact version is InstantAllegianceArtifact. The amnesia-induced versions are CriminalAmnesiac (Face/Heel) and AmnesiacsAreInnocent (Heel/Face). Compare MoralityDial.
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!!Examples:

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[[folder:Anime and Manga]]
* ''AkazukinChacha'': "Red Riding Hood" Chacha does this repeatedly to an assortment of good guys and villains. Evilness is (usually) visually signified by black and purple eye makeup, which vanishes if a person is de-eviled.
* ''Manga/SoulEater'' has one of these in the form of Arachnaphobia's creatively named 'Morality Manipulation Machine'. It's exact use in the anime and manga differs. In the anime, a large network of them are used for a WorldWreckingWave with the goal of directly making people go insane. In the manga it fits more in this trope, causing Kim and Jackie to have issues with inhibitions and moral dilemmas like 'not trying to kill friends with fire'.
* ''Anime/SailorMoon'' has versions of this in the first, second, and fifth seasons - which are not 100% effective when used on the main characters: [[spoiler:Tuxedo Mask, Chibiusa and Uranus/Neptune respectively.]]
* The ''{{Slayers}}'' OVA "Mirror, Mirror" had the Shadow Reflector, a device that creates a double of anyone reflected in it with an inverted personality who is loyal to the person who held the mirror when it was created. Unfortunately, instead of creating an EvilTwin like the villain hoped for, it just reverses all their character traits, resulting in a Lina Inverse double who is a sniveling humanitarian.
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[[folder:Comicbooks]]
* The ''ComicBook/FantasticFour'' villain, the Wizard, has a gizmo like this (he doesn't use it that often). He once used it to turn the Thing bad, but of course it didn't last. Decades later, he used it to turn the [[HeelFaceTurn reformed]] Sandman [[StatusQuoIsGod back into a bad guy.]]
** One reason he doesn't use it more often (although it'd been around for a while by that point) is that he tried it on the Thing again shortly after Johnny Storm's wedding. However, by that time the Thing had gotten DarkerAndEdgier--essentially, he was already enough of a "bad person" that the device had no effect. It also may not have helped that the Wizard was [[MoralEventHorizon about to use it on Franklin Richards.]]
* 50s-vintage CaptainAmerica fell afoul of the [[DirtyCommies evil Soviet scientist]] Stanoff and his ''[[ObviouslyEvil Virus of Evil]]''. The virus turned Cap into a [[{{Anvilicious}} clueless-liberal Soviet apologist]].
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[[folder:Literature]]
* The early ''Franchise/DocSavage'' stories had the titular Doc rehabilitate criminals through "delicate brain surgery." [[ScienceMarchesOn You can sure as hell bet that wasn't in the later versions.]]
* ''Literature/VillainsByNecessity'': The major unethical act of the main 'good' wizard in this story is to invent a spell which brainwashes the evil out of villains, permanently. (Not a spoiler because it's explained in the first chapter or so.)
* TheWheelOfTime has a magical method of turning channelers to the Dark against their will using 13 Black sorceresses channeling through 13 Fades. This causes previously good characters to realize that EvilFeelsGood and start serving the Shadow. It is not known if this process is reversible, but the implication is that it isn't.
* In Creator/SeananMcGuire's ''Literature/VelveteenVs The Junior Super Patriots'', in the BackStory, this was accidentally and gradually done by one of the first superheroes to the other two: no one knew that she drained goodness as well as beauty out of her surroundings.
* ''SpockMustDie'': in this early StarTrek novel, a machine used by the Klingons to suppress the Organians has the side effect of creating a mirror version of Spock, right down to the molecular level. Curiously, this biological mirroring also reverses Spock's allegiance, making him a Klingon agent.
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[[folder:Live Action TV]]
* Played with on ''TheMentalist''. When Patrick Jane's former psychiatrist asks for his help, he and the CBI agents investigate a murder at a college campus. Jane meets with a group of researchers who are investigating human morality by testing a machine on human subjects. The machine sends impulses to the morality center of the brain, which the researchers believe will turn "evil" on and off at their discretion. Jane finds out that the results have been falsified, and the machine does nothing. This was done to keep the truth from the head researcher so that he will keep funneling money into the university. Jane's gambit near the end is to make the team believe that they have succeeded. Jane's psychiatrist friend uses the machine on him to turn him evil, but doesn't turn him back, so when Jane takes a gun and confronts the chancellor of the university, everyone not in on the con believes that he will kill because he has no morality to keep him from doing it. He shoots his friend (with blanks, of course), causing the murderer to confess in a panic.
* In the two-part story Ali Baba, the titular villain kidnaps Professor Nabakov and, when ''Series/ElectraWomanAndDynaGirl'' catch up with them, uses his Metamorphose formula to turn Judy evil.
* In ''Series/StarTrekTheNextGeneration'', [[EvilTwin Lore]] manages to convince Data to join his evil plot by deactivating Data' ethical program.
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[[folder:Newspaper Comics]]
* The ''ComicStrip/FlashGordon'' comic strip once had a storyline in which Ming the Merciless invented a device along these lines, which was turned on him in the end; he became a cheerful, friendly individual ([[BaldOfEvil with hair!]]) who immediately agreed to become Prince Barin's "[[GildedCage guest]]". The effect actually lasted a considerable period of time, allowing the writers to take Flash on a variety of different, non-Ming-related adventures for a while.
* ''BloomCounty'''s Steve Dallas had his brain "Gephardtized" and became a sensitive, new age guy.
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[[folder:Tabletop RPG]]
* There was a ''DungeonsAndDragons'' item called the Helm Of Opposite Alignment that did this to whoever wore it. It was speculated that if it were to be put on the head of an angel-equivalent, all of creation would be in trouble.
** Fortunately, the angel-equivalents have pretty good Will saves, at least in 3.5.
** What makes the helm dangerous is that it isn't a temporary effect - the alignment change is permanent even after the helm is removed. What's more, even though the victim usually knows what happened, the change is thorough enough that they ''enjoy'' their new alignment and view the prospect of going back to their old ways with horror.
*** [[FridgeLogic So just knock them unconscious and put a second Helm of Opposite Alignment on them to reverse the effects.]]
** In the first edition ''Dungeons and Dragons'', ''Oriental Adventures'' supplement, the spell Compel allowed the shukenja casting it to change the [[CharacterAlignment alignment]] of the target creature to whatever he wished, including the exact opposite.
** The Book of Exalted Deeds has a spell called Sanctify the Wicked that traps an evil being in crystal and forces them to undergo evil-eradicating therapy over the course of a whole year. Once the spell ends, the creature is now good, having all their evil (and evil abilities, if any) trimmed away and replaced with goodness. (Plus some level adjustment, even if it lost more stuff than it gained.) This even works on AlwaysChaoticEvil beings like demons.
*** Its sister supplement, The Book of Vile Darkness, has the spell Morality Undone, which turns a character or creature evil. The spell's description specifies that they don't turn against their friends instantly, but it ''does'' make spells like Suggestion or Charm Person much more flexible (those spells only let you suggest actions that are within a person's nature).
** A certain mace in D&D requires its wielder to roll Will saves or become chaotic evil. It also requires being bathed in blood every day or else it stops having any magic effects. [[{{FridgeHorror}} And when you realize that a mace is a cleric's weapon...]]
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[[folder:Video Games]]
* ''{{Nethack}}'', being loosely based on ''DungeonsAndDragons'', also included the Helm of Opposite Alignment. Although it's not permanent in this game.
** Though nine times out of ten the actions of a lawful character and a chaotic character are the same anyways, unless you make a habit of using poisoned weapons. The main effect of switching alignment is to lose all your divine protection (permanently, because the gods are jerks), and to allow you to use altars of a different alignment.
* A text adventure centered around your attempts to escape from such a machine. The final reveal was that [[spoiler:both sides in a war had built such a machine and nobody can remember what the war was ever about]].
* ''PerfectDark'' has the Psychosis Gun, which essentially polarizes the morality of Mooks to make them sidekicks.
* Eiki Shiki from ''VideoGame/{{Touhou}}'' has "Judgment - Cleansed Crystal Judgment," her spell card in which she uses a mirror that reflects the player character's sins. The result? Your reflection attacks you. Though this is explanatory; with Eiki being a supreme judge of Hell, she is a sentient morality machine herself, so having a mirror with this function makes sense.
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[[folder:WebComics]]
* In ''Webcomic/{{Sinfest}}'', [[http://www.sinfest.net/view.php?date=2009-01-24 Jesus can zap succubi into goodness.]] [[http://www.sinfest.net/view.php?date=2009-02-04 Satan can zap one back.]] [[http://www.sinfest.net/view.php?date=2009-02-07 Which surprises him about the other.]] His powers have changed over the course of the work: [[http://www.sinfest.net/view.php?date=2012-03-14 The Buddha enlightened some drones and he didn't even try to revert them.]]
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[[folder:Western Animation]]
* In the ''WesternAnimation/BeastWars'' episode "Dark Designs," this was how Megatron turned Rhinox evil. Fortunately, it could undo itself, which Megatron was grateful for when that action turned out to be [[BewareTheNiceOnes a]] ''[[BewareTheNiceOnes bad]]'' [[BewareTheNiceOnes idea]].
** And then, in ''WesternAnimation/TheTransformers'', there was Megatron's "personality destabilizer device" from "Day of the Autobots," which turned nearly ''all'' of the Autobots evil, until their human sidekicks worked up a reversal device.
** Megatron has a ''loooooooong'' history of these things, since "The Secret of Omega Supreme" reveals he had one about nine million years ago, inaptly christened the Robo-Smasher, what with it not actually smashing anything. He used it to corrupt the then-good Constructicons, and then tried to use it on Omega Supreme. Omega managed to destroy it halfway through his own reprogramming, with the effect of turning him permanently into a TinMan (pardon the double-meaning) with anger issues. Megs apparently was [[NoPlansNoPrototypeNoBackup never able to rebuild the sucker.]]
* One of these appears in ''WesternAnimation/KimPossible''. Specifically, it switches Ron's and Doctor Drakken's morality; Ron becomes a much more competent villain than Drakken ever was, and Drakken becomes nice. A later episode upgrades it to a straight morality reversing ray, resulting in people's alignments getting flipped left and right. [[TheyWastedAPerfectlyGoodPlot No villain-Kim though]].
* Done on ''WesternAnimation/XiaolinShowdown'' - going to the Yin-Yang World with either the Yin Yo-Yo or Yang Yo-Yo, but not both combined, switches the morality of the user upon re-entry to the "real" world.
** It was hilariously abused in one episode, when Kimiko and Wuya fought in Showdwon using one of yo-yo's each. They were changing alignments so much and so fast it's a miracle they come out with their original personalities at the end.
** When Omi is mirrored, he seems mostly interested fighting for its own sake. Chase Young comments that "Omi's dark side doesn't seem to be all that... dark.".
** After using the Yang Yo-Yo, Jack Spicer is nice to the point of being annoying to the protagonists, and later voluntarily uses the Yin Yo-Yo to help his new friends, even though he knows it will turn him evil again.
* ''WesternAnimation/SilverHawks'' has a cosmic alignment reverse the heroes' ''and'' villains' morality, which results in Mon*Star and his gang using ThePowerOfFriendship (or better teamwork compared to the now squabbling and villainous [=SilverHawks=]) to beat them and put the [=SilverHawks=] behind bars! Amusingly, Mon*Starr and his gang grow bored of not having any more bad guys to catch, and then the effects wear off and they start their petty crimes again with the [=SilverHawks=] safely behind bars.
* ''CareBears Adventures in Care-a-Lot'': Grizzle accidentally created one of these. He sent a robot with an Eraser Ray down to Care-a-Lot to get rid of the Care Bears' belly badges, but instead, the ray flipped the badges, making the bears only care about [[PlanetOfHats their personality trait]], causing them all to fight with each other instead of getting along.
** The CareBearStare itself acts as this from time to time, filling the target with good feelings that make them forget their evil ways. It wears off after a while, apparently.
* In ''WesternAnimation/PhineasAndFerb'', Dr. Doofenshmirtz created a Turn-Everything-Evil-inator in order to make [[WeCanRuleTogether Perry the Platypus his ally]] in "Day of the Living Gelatin." Perry turned out to be too nimble to be hit, but a number of other things were hit, including a bar of soap, a toothbrush, and a [[ItMakesSenseInContext swimming pool full of grape and curry flavored gelatin]].
** Also, the Misbehavinator from "Got Game?" ended up being one of these, though probably not intentionally. Created to make the other dogs at a dog show misbehave, it also made Buford (accidentally hit by it) admit to Isabella that he was wrong, prompting Ferb to comment, [[OutOfCharacterMoment "That was completely out of character."]]
** Later Doofenshmirtz builds an "Ultimate-Turn-Everything-Evil-inator" to try to turn Major Monogram evil, but accidentally hits Carl instead.
** In "Bullseye!", Phineas and Ferb's dad Lawrence accidentally stumbles into a contest to choose the absolute leader of the mad scientist group L.O.V.E.M.U.F.F.I.N. He gets his butt kicked in the first two contests, but then gets hit by Doofenshmirtz's Turn-Everything-Evil-Inator (either that or "Rodney" von Roddenstein's Turn-Everything-Evil-Izer) and sweeps the "Evil Glaring" competition.
* ''{{Bionicle}}'': The evil scientist Makuta, Mutran, created mutant Shadow Leeches so that they can drain a target's moral light. Takanuva was partially affected, but still retained his moral self and the additional powers over shadow. Fortunately, all those affected were cured by the screech of a bat-like Klakk
* An ''WesternAnimation/EarthwormJim'' episode featured a device that created an opposite duplicator. Evil Jim tries to create an evil FiveManBand out of Jim's TrueCompanions, but finds out the inherent problems with it when ActionGirl Princess Whatshername becomes a useless evil ValleyGirl, mild-mannered Peter Puppy (who transforms into a rampaging beast) becomes a sociopath who turns into a GentleGiant, and Evil Jim ends up getting hit numerous times, creating an army of Jims.
* The Cat Catcher in ''Animation/CatCity'' is this. It is a huge metallic bulldog that eats [[CatsAreMean mean, wild, murderous, mouse-eating cats]] and shits [[CuteKitten cute, peaceful kittens]]. In the sequel we learn that the bows on the cats' tails are responsible for the change.
* [=McNasty's=] "Mean Machine" in ''The Legend Of Big Paw''.
* Twilight Sparkle mentions having access to at least a few "[[BrainwashingForTheGreaterGood Reform Spells]]" in ''[[WesternAnimation/MyLittlePonyFriendshipIsMagic Keep Calm and Flutter On]]''. Thankfully, at least [[NightmareFuel when you consider the potential of such a thing]] and ''especially'' what happened [[GoneHorriblyRight the last time Twilight screwed with ponies' minds]], [[RealityWarper Discord]] [[ItMakesSenseInContext eats the pages from her books that contain the spells.]]
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