Masked Mutant: What? You tricked me! The great Masked Mutant, tricked by a boy!
A.k.a. Bet You Can't Make Yourself Really Small... (a.k.a. Bet You Can't Fit in This Bottle, a.k.a. Let's See You Turn into a Mouse...)
Easy: the mortal just needs to trick the villain into turning into something he can defeat, or to enter a container in which it can be trapped! This is usually done by appealing to the shapeshifter's ego, either through flattery or through dismissive skepticism:
"Wow! What an impressive lion you are — I bet you make a gorgeous cat! Ooh... what about a mouse? Can you do that?"
"Pshaw! You expect me to believe that a djinni your size came out of that tiny bottle? Ha! I'll believe it when I see it!"
This could be how the Evil got Sealed in the Can. Lately, some shapeshifters have started becoming aware of this ("Did you honestly think I would fall for that old chestnut?"), but it is still played straight as often as it is subverted. Compare with Assimilation Backfire.
- In the Super Mario Bros. anime The Great Mission to Save Princess Peach!, Peach convinces Bowser to entertain her by demonstrating his shapeshifting powers. Her last request is for him to turn into a teddy bear, and when he complies she stuffs him in a small chest. Then Bowser morphs out of the chest and back to normal, subverting whatever plan she had in mind.
- Back in Dragon Ball, when Piccolo was still a bad guy and faced off against Goku, he at one point made himself grow much larger. Goku, somewhat impressed, remarked that if only Piccolo could become even bigger he might be in trouble. Piccolo promptly did so... and Goku flew down his throat to retrieve the Sealed Good in a Can that he had previously swallowed. Thanks, Piccolo.
- The Pokémon anime actually subverts this with the Orange Islands match against Drake. His first Pokemon is Ditto, and when it's suggested to Ash to switch out Pikachu after Ditto changes into him, he says Ditto would just transform into the next one sent out.
- Shows up in The Sandman, with Lampshade Hanging, during the sequence where Lyta is hallucinating and/or shifting between seeing the real world and the Dreaming.
- In a Mighty Mouse comic book, there's a story called "The Bad Genie". The genie, a cat of course, is a Card-Carrying Villain who forces the mouse who freed him to serve him, and also pushes aside some houses so he can stretch out. After brute force, Mighty Mouse tries the "bet you can't fit in your lamp again" gambit, but he's too tired to argue...
- In an issue of JLA, Batman uses this tactic against the all-powerful Metron. Metron prides himself on his knowledge and has never been a human, so Batman convinces him to take on a flesh and blood form to see what it's like. Then Batman punches him in the face, drugs him and steals his Mobius Chair.
- This is one of the few ways to defeat the Absorbing Man, who can duplicate most superhuman powers and just about any material substance (though he nearly always needs physical contact) — get him to turn into something inconvenient or that is more than his powers can handle.
- In his first appearance, The Mighty Thor made him touch helium, so he turned into helium and floated helplessly into space, though that raises the question of why he doesn't turn into the oxygen, nitrogen, and CO2 in the air already.
- Transforming can't be subconscious, or he'd always be made of the same stuff as his Magic Pants, or indeed the air. But it would be in-character for him to deliberately transform to anything he touches unexpectedly, as a defense mechanism against a possible attack. After all, all these attacks inconvenience him but he recovers eventually, whereas if he touched acid and didn't transform, he'd just die like a human. However, the numerous times he's defeated by getting him to absorb something he doesn't want to and isn't an active threat demonstrates that he does not have full control over his powers.
- This can lead to Hoist by His Own Petard when the Absorbing Man overestimates what he can handle. One fight with the Incredible Hulk led to him trying to absorb the power of the very Earth itself, only to explode when the Earth's power proved too much for him to absorb. He recovered. Eventually. Another time, the Absorbing Man fought the Hulk and made the mistake of breaking glass over him, and accidentally took on a shard's properties when it fell on him. All the Hulk had to do then is throw one punch and he shattered his enemy.
- Also, he shouldn't go up against guys who know chemistry. Spider-Man once got him to absorb one thing, then sprang his trap: dumping a ton of something that reacts explosively with what the Absorbing Man had become. Kaboom. (He recovered. Eventually.)
- In one particularly humiliating defeat, She-Hulk beat him when he attacked her in an aquarium in the Mall of America by simply waiting until he realized he was ankle-deep in water and turned into it, causing him to flow down a nearby drain into the sewer.
- Wonder Woman goaded The Queen of Fables into turning into a dragon, then quickly buried axes in her eyes.
- In the 1994 Milestone/DC crossover Worlds Collide, some children try to goad Eldritch Abomination Reality Warper Rift into transforming to a smaller, less powerful shape. He's just amused and commends them for trying, since he admits the ploy might have worked if he'd fallen for it.
- In his first battle with the Sandman, Spider-Man feinted an attack with a power drill. The Sandman evaded it by turning into a cloud of dust, only for Spidey to jump through him and grab an industrial vacuum cleaner, then hoover up his foe.
- Puss in Boots tricks a shapeshifting ogre into becoming a mouse, then eats him.
- The original version of The Sorcerer's Apprentice has the apprentice tricking the evil master into turning into a drop of water, which then falls into a river.
- There was also a story where the shapeshifter turned into a fish (swimming in a river) as part of a chain of transformations to show the normal hero his power. The shapeshifter says he'll change from the fish into a mountain, but the hero says he'd be more impressed if the shapeshifter could change into a drop of water. He does, and washes away with the river.
- Wiley and the Hairy Man has Wiley do this to the shapeshifting Hairy Man as one of the three tricks he has to pull.
- Sort of used in Aladdin, where Aladdin does this to Genie to get himself out of the cave without wasting a wish. Though Genie doesn't do any shapeshifting, he does take the Schmuck Bait out of sheer ego. Later, Aladdin tricks Jafar into wishing to become a genie, which immediately causes him to be sucked into a lamp. However, Jafar does need Genie to do this, so he couldn't do it all on his own. It did, however, use up Jafar's final wish and prevent him from using his powers (which the Genie had already made quite vast with a previous wish) against Aladdin; he may have been stronger as a genie, but genies are incapable of killing anyone.
- Alluded to in the "Mickey And The Beanstalk" sequence in Fun and Fancy Free. Mickey very nearly talks Willie the Giant into turning into a housefly; unfortunately, Willie insists on changing into a pink bunny instead, upon which he notices Mickey, Donald, and Goofy going for the giant flyswatter.
- Mexican children's film Katy Meets the Aliens has its animal heroes trick the shapeshifting Alien X into turning into a balloon so they can pop him with a pin. It takes him out of action long enough for them to free his prisoners, but he eventually reforms into a horrific monstrosity.
- In Fantagiro the heroine tricks the Black Witch into transforming into a crystal — which she shatters.
- In Underworld: Awakening, Selene runs into a tunnel too narrow for Quint's Uber-Lycan form to enter, so he returns to human form and follows her. Although he is still rather powerful in his human form, it was enough of an opening for her to kill him.
- Ghostbusters (1984): When Gozer demands that the Earth choose the shape of its destroyer, Ray immediately thinks of The Stay Puft Marshmallow Man, assuming the character would be the one thing that could not possibly ever harm anyone. It's subverted when it turns out a 100 ft tall version of the character is actually very much capable of mass destruction.
- In Ghostbusters (2016), Rowan offers to take the form of whatever the women want for the final battle. Holtzmann tries very hard to take advantage of the situation and suggests a bullseye. Rowan instead becomes a gigantic version of the Ghostbusters' logo ghost, which they had thought was a safe option.
- "The Fisherman and the Djinni" from One Thousand and One Nights (better known as Arabian Nights): The fisherman feigns skepticism to trick the djinni into returning to its bottle, which he promptly stoppers. Possibly the Ur-example of this trope.
- Referred to (and subverted) in Starik Hottabytch (Old Man Hottabytch) by Lazar Lagin. A Jackass Genie almost falls for the trick, but at the last moment remembers that "a thousand one hundred and forty-two years ago a fisherman fooled me in just the same manner.".
- Puss In Boots from Puss in Boots tricks the ogre into turning into a mouse, which Puss eats.
- This is presumably why Puss has the reputation of being a "Notorious Ogre Slayer" in the Shrek series. However, neither Shrek nor Fiona has shown any signs of being magical. While we don't know about other Ogres yet, it'll be interesting to see how the writers deal with this in Puss In Boot's long-teased origin story film.
- Similar thing happened in a story of Brazilian Big Eater Magali: she tricked a shapeshifting villain into turning into a roasted chicken with potatoes...
- In Mercedes Lackey's retelling of Puss in Boots, Reserved for the Cat, Thomas attempts to trick a troll into doing this. Unlike the ogre in the original however the troll is not an idiot, and shifts again to catch the cat by the throat when he pounces.
- The Bartimaeus Trilogy: When Kitty tries to pull this on Bartimaeus, he scoffs at the idea that he would be dumb enough to fall for one of The Oldest Tricks in the Book. He notes, however, that had it worked this would be a very powerful binding charm since he would have entered of his own free will.
- It's implied that it's happened to him at least once in one of his footnotes in Ptolemy's Gate. Which would explain why he would know why the charm would be so powerful.
- The Goosebumps book "Attack Of The Mutant" had a shape-shifting villain from a comic book actually be real. Early on, we're told that if the villain turns into liquid, he can't change back. A kid claimed to be a superhero who could only be killed by acid, so the villain turns into acid, and thus is another Chekhov's Gun fired.
- This is one fundamental strategy for dealing with a boggart in Harry Potter. As it automatically assumes the shape of your greatest fear, tackling it in a group may cause it to try and combine two different fears - and end up with something less scary than either.
- Animorphs: The team defeats David by using an elaborate version of this ruse: they trick him into turning into a mouse to enter a miniature labyrinth with Rachel (by pretending that the MacGuffin he tried to blackmail out of them is there). Rachel escapes the labyrinth, David stays locked inside until he enters Shapeshifter Mode Lock, since he wouldn't be able to demorph without being squished like a pancake.
- Used rather cleverly by Jon-Tom to escape the mimicvines in the Spellsinger novel The Moment of the Magician.
- Although not intentional, Mulgarith the ogre in The Spiderwick Chronicles is defeated when he turns into a bird to get away and ends up eaten by Hogsqueal, who just happened to be hungry at the time.
- While not a shapeshifter itself, Com-Pewter had the power to summon anything to serve it. The heroes escape its chamber by verbally expressing fear that it will summon a female egret — in other words, an egress.
- There is a German book named Krabat that, even though it is shapeshifter vs. shapeshifter, has Krabat win a fight with a much alike trick: When trying to hide (there are more attempts before this one), he turns into a corn and hides between other corns that a girl is feeding to chicken. After being thrown onto the floor, his enemy transforms into a chicken and starts picking the corn. Once he is close enough, Krabat transforms into a fox and quickly bites off the chicken's head.
- In the Are You Afraid of the Dark? episode "The Tale of the Fire Ghost", the ghost is defeated when one of the kids claims that he's terrified of fire and begs him not to turn into its fire form. The ghost promptly does so...activating the sprinkler system.
- Doctor Who:
- "The Eleventh Hour": The Doctor is able to uncover the escaped Prisoner Zero by tricking it into attempting to disguise itself as... itself. Specifically, it's taking the form of whatever Amy Pond is thinking about. So he gets her to think about the true form of Prisoner Zero.
- "The Day of the Doctor": Queen Elizabeth I has been impersonated by a Zygon shapeshifter. She later turns out to be the real Elizabeth, who killed her alien copy and is now Impersonating the Evil Twin, given that the other Zygons would never believe a mere human female would overcome one of them. There's a Historical In-Joke when explaining how she did this. Brandishing a Chastity Dagger the Queen says, "I may have the body of a weak and feeble woman... but so did she!"
- Wembley gets rid of the Mean Genie this way on Fraggle Rock.
- Lampshaded in Star Trek: Deep Space Nine. A little girl tells the real shapechanger Odo a old fairy story about a hero named the Great Minra who tricked an evil changeling into turning himself into a loaf of bread. To her surprise Odo gets to the end first ("The Great Minra gobbled him up"), and when she asks how he knew Odo wearily points out that the fictional changeling wasn't very smart.
- And when the girl asks Odo to turn a loaf of bread, he asks; "Why? So you can gobble me up? I don't think so."
- Further subverted in one novel to series where Odo warns off a Cardassian with a tale about how he voluntarily transformed himself into some food the certain alien liked, allowed himself to be eaten, and then expanded in the alien's stomach, ripping him apart. (It's implied that Odo's lying about having actually done that, but the fact that he could do that is terrifying enough).
- The Thrilling Adventure Hour:
- In the Beyond Belief episode "Wishing Hell", Nightmares the Clown's attempts to frighten Sadie Doyle fall short because she finds clowns, even Monster Clowns, hilarious. He decides to show her his true form, that of a giant spider. Frank exclaims that Sadie is deathly afraid of spiders, only for Sadie to correct him and point out giant spiders don't scare her, only regular teeny tiny spiders due to how they can creep up on one when they're going through their liquor cabinet, innocently trying to collect a bottle. She pleads with Nightmares not to turn into a teeny tiny spider lest she actually become afraid. Nightmares does exactly that, and promptly gets stomped on by Frank.
- The Beyond Belief episode "When Cthulu Cthalls", Frank and Sadie are up against a pair of Hollywood Jehovah's Witness peddling a particularly old god. When said old god makes an appearance, it has a loss of confidence due to its age. Sadie convinces it to possess a nearby lamp, which she then turns off and unplugs.
- In Greek mythology, Zeus realized that he had to get his mistress, Metis (goddess of prudence and magical cunning) out of the way, since it had been prophesied that she would bear powerful children, and he feared being assassinated. He suggested that they play a "game" of changing shapes, and, when she turned into a fly, he swallowed her whole. She was a pretty good sport about the whole thing, and from thereafter she lived inside his head, giving him good advice. She also gave birth to their daughter, Athena, who had to be delivered via skull (and so, despite Zeus' claims, he did not create Athena alone). And it turns out that Zeus's fears were unfounded because while Athena was very powerful, she was also completely loyal and devoted to her father.
- Kecleon changes type depending on what attack is used on it. You can use an attack, then one of a type that is strong against the previous attack's type for massive damage. In some cases, you don't even have to use more than one type. Ghost- and Dragon-Types are both weak against their own type, though Kecleon's default type is Normal, which is immune to Ghost attacks.
- Porygon's Conversion move works similarly, though Conversion (which turns into a type strong against the one used) is much more difficult to exploit since there's the element of chance involved. Of course, in both cases Porygon doesn't even have to use either move, but you know, just in case...
- The transforming Ditto can't change forms until the battle ends, so once it transforms it's locked in that form. This means you can potentially control which Pokémon it becomes for the purposes of using a Super-Effective attack against it.
- The same tactics are used to trick a verbal shapeshifter in Knights of the Old Republic, enabling you to use his voice mimicry to break a voice lock. Whether said shapeshifter is tricked or just doesn't care is up to discussion. Paraphrasing : "...the morality chip most droids are believed to possess forbids me from mimicking a human voice."
- The final battle in King's Quest V has the hero engage in a shapeshifting duel with an evil wizard. After his first three forms are countered, the wizard gets mad and transforms into a raging fire... which is when that raincloud spell you just learned comes in real handy.
- In Captain SNES: The Game Masta, Alex comes up with a (fake) plan to get rid of the personification of his hatred, which resembles Zeromus. He will get really angry, causing "Zeromus" to grow so big that he'll explode. Alex points out that the only way Zeromus can counteract this plan is if he can deliberately shrink himself. Zeromus demonstrates that he can deliberately shrink himself... by shrinking himself to be just small enough to fit into Alex's unbreakable jar.
- In Darken, this is how a possessing spirit came to be trapped in the gem in Komiyan's sword Blackshard. It's had a very long time to find the weak points in its prison.
- The "Contains One Space Battle" story in the webcomic Goats has Jon and Phillip meeting God after Phillip argues he doesn't exist. God appears as a pirate named Larry, and explains he can take many forms, such as a slightly taller pirate named Sebastian. The guys are unimpressed, and God tells them to pick a form. Phillip suggests a pork chop. God becomes a pork chop, then Phillip eats him, thus winning the argument. This is, incidentally, both a pivotal event behind the later plot-driven era of the comic and the least kosher meal ever imagined.
- Parodied in Van Von Hunter when the title character faces a vampire that can switch between human and monstrous form. "A beautiful woman is so much more intimidating than a vampire." Two panels later, "They are easier to stake, though."
- Similar to the Aladdin example, in Danny Phantom special "Reality Trip", Danny played upon evil ringmaster Freakshow's envy of ghosts so that he'd use the all-powerful Reality Gauntlet to become a ghost. This ended up making him susceptible to Danny's Fenton Thermos.
- Ben 10: Alien Force: Vilgax finally succeeds in stealing the Omnitrix but can't get it to work for him. Ben volunteers to show him if he releases his friends. Ben uses this opportunity to set the Omnitrix to turn Vilgax into Goop, a giant amorphous blob of gel, and steals the anti-gravity device the alien needs to maintain its shape, reducing Vilgax to a puddle. Ben then just plucks the Omnitrix off his melted form.
- The Avengers: Earth's Mightiest Heroes!:
- The Absorbing Man touches Thor's hammer Mjölnir and converts himself into metal that can harm a god. Thor, however, points out that he can control Mjölnir, and can therefore control Absorbing Man, whom he uses as a human-sized hammer for the rest of the fight.
- Counting against Absorbing Man, even in the comics, is the fact that he's dumb as bricks. He doesn't even need to be tricked into turning into something the heroes might have an advantage against. Still from this cartoon:
Hulk: Hulk smash rock, Einstein.
- Aladdin: The Series:
- Used straight in the episode "Sands of Fate". Genie needs to stop a caravan from proceeding. Aladdin who is at that time a guardian of said caravan (long story) offers him to settle the matter by tossing a coin. Aladdin then makes it so that the coin falls into a bottle and the helpful simpleton Genie volunteers to retrieve it. It turns out that even a freed Genie cannot escape from a sealed bottle. Go figure.
- There's also the time in "My Fair Aladdin" when Mechanicles trapped Genie in a bottle by simply asking him if he could remove the model ship that was inside.
- In the Garfield and Friends retelling of Puss in Boots, Garfield manages to trick the ogre resident of a nearby castle into turning into a roach, which he then squishes with his high-tops. Unfortunately, at the end of the cartoon, it's revealed the ogre survived, forcing Garfield to put his high-tops to use in running for his life.
- In Alfred J. Kwak, this is played straight and subverted with the Evil Spirit of Darkness.
- The spirit was defeated hundreds of years ago by a traveler who tricked him into going back into his bottle, and then sealed him shut.
- When Alfred tries the same thing later on it almost works, but the spirit then remembers the details of how he was resealed again, and stops halfway through. Alfred only succeeds when he realizes that the Evil Spirit can be hurt by light, and forces him back in.
- In the Transformers Animated episode "TransWarped", Henry Masterson uses his Headmaster unit to take over Starscream's headless body and go on a rampage. Optimus Prime goads him into trying out Starscream's jet mode, saying a n00b like him wouldn't be able to figure it out. Enraged, Henry tries it, but the transformation process makes the jet mode's nose cone smack him in the face and knock him out of Starscream's body.
- Several times, Blitzwing gets tricked into transforming into his tank mode while still in midair in jet mode, sending him plummeting to the ground. The trick is that Blitzwing's multiple vehicle modes are tied to his multiple personalities, and which personality is in charge can be influenced by his mood.
- An accidental example occurs in The 13 Ghosts of Scooby-Doo. When Scooby faces the ghost wizard Maldor with a magic scepter, he turns himself into a fly to hide from him. Maldor turns himself into a frog to catch Scooby. A frog that is small enough to be trapped in the Chest of Demons.
- Miraculous Ladybug:
- Animan's power is shapeshifting into any animal he wants. Cat Noir figures they can trick him into shifting into something small and trap him in a cookie box at the Dupain-Chengs' bakery, but Ladybug points out that it won't prevent him from shapeshifting into something bigger and breaking out. They do use the box to catch him (he'd taken the form of a ladybug, nice choice), but then lure him into a bus after he shifts into larger forms. Then he shifts into a T. rex, and any thoughts of caging him again are abandoned.
- Chameleon's power allows her to become anyone she kisses. Ladybug tricks her into kissing a clam, which she immediately transforms into. Since Chameleon has to kiss someone to change forms, she's trapped in the form of a clam and getting her akuma is as simple as having a waiter pry it open.
- Occurs in a second season episode of The Secret Saturdays when Zak and Fisk encounter a large predator cryptid that can shapeshift to adapt to its environment (becoming serpentine to move through swamps, growing armor to crash through trees, etc.). Zak is finally able to capture the beast by tricking it into chasing him into a swimming pool. The cryptid shifts into an aquatic based form as Zak climbs out the other side and Fisk closes the pool's top. Since the creature could only adapt to its present environment, it couldn't alter its body to try to escape and was effectively trapped.
- In T.U.F.F. Puppy episode "Share-A-Lair", after it's revealed that Chameleon posed as T.U.F.F and D.O.O.M's new field agents to set them against each other, Dudley claims he doubts that Chameleon was T.U.F.F's mouse agent, stating it was too realistic for Chameleon to change into. Chameleon takes offense to this and proves it was him by turning into a mouse. Unfortunately for Chameleon, this resulted in Agent Jumbo stomping on him.
Chameleon: [dazed] See? It fooled the elephant.