- Inverted in the Adventures of Sonic the Hedgehog episode "Tails' New Home", when Sonic sees through Robotnik's plot by realizing that if the fox family was Tails' real family, they would have called him by his real name, Miles..."...not the name I gave him.note Something smells, and I bathed this morning!"
- American Dad! spoofs this in the episode "It's Good to Be the Queen", where Stan ends up in a situation where he takes the homecoming queen from Francine's high school class to a reunion dance, while his body double Bill stays with Francine trying and failing to keep her away from the dance. When Francine realizes Stan duped her, she pulls out his gun and holds up both of them, threatening to shoot out Stan's kneecaps, but quickly finding it impossible to tell which is Stan and which is Bill when they get into a brief scuffle and the flowers on their otherwise-identical suits fall off. One promptly steps forward to give a heartfelt apology and promise that he truly loves Francine - which convinces her that he's Bill, because the real Stan would never say something that sweet. She promptly shoots the other one's knee - only for it to turn out it really was Stan and she just crippled Bill.
- Played for Laughs in the American Dragon: Jake Long episode The Doppelganger Gang, after Trixie and Spud discover that Jakes been using chi doppelgangers to help out with his swamped schedule.Spud: How do we know that this ones the real Jake Long, and not the other one?
Jake: Spud, trust me.
Spud: I could trust you or you could tell me what my favorite possession is!
(*Beat* as the doppelgangers all give him an odd look)
Jake: A ball of bellybutton lint youve been collecting since you were 3.
Spud: Eugh, thats disgusting! And also correct, so Im choosing to believe you for now. But Ill be keeping my eye on you.
- At the end of Batman: The Animated Series episode "Beware the Gray Ghost", Bruce Wayne tips off Simon Trent to his identity by repeating something he said to him earlier as Batman.
- Happens twice in Ben 10. When Ben turns into Heatblast for the first time, a horrified Gwen doesn't recognize him and is about to use a fire extinguisher on him when he says "Don't even think about it, freak". This is when she realizes it's Ben. The second time is in A Change of Face when Gwen and Charmcaster have exchanged bodies and the real Gwen must convince her family of her identity. The following conversation takes place:Charmcaster (as Gwen): Who are you guys going to believe? This liar, or your own eyes?
Gwen (as Charmcaster): Ok, if you're Gwen, you should know the name of the teddy bear Ben sleeps with.
Ben: Hey! Furry Freddy has his own bed! It just...happens to be next to mine.
Gwen (as Charmcaster): (facepalming) You just gave her the answer, you dweeb! Did your parents send you to doofus school, or were you born like this?
Ben: (wide-eyed) Gwen?! It really IS you!
- And in the Ben 10: Alien Force episode "Time Heels", Gwen goes back in time to stop Kevin from mutating. After freezing time for everyone except the Gwen from that time period, she assures her past self that she is her from the future by whispering an embarrassing secret in her ear. This happens when Gwen goes back in time again to undo the Bad Future she accidentally created.
- In Boo to You Too! Winnie the Pooh, when Piglet has barricaded himself in his house terrified of Halloween and Pooh rings his door bell, Piglet suggests that Pooh say something only he would say before letting him in. Pooh asks Piglet what he should say and Piglet says, "Well possibly, 'I am Pooh'", to which Pooh responds, "You are? Well then who am I?", which convinces Piglet.
- In the Code Lyoko episode "Xana's Kiss", the heroes are dealing with a polymorphic clone that keeps changing shape. When this turns into a case of Spot the Imposter where Odd has to tell the Clone from Yumi, he quickly determines which is the real Yumi when the Clone stays silent while the real Yumi calls him a "pea-brain". Odd may be insulted a lot, but he knew that XANA would never call him "pea-brain".
- In Codename: Kids Next Door movie Operation: Z.E.R.O., Numbuh 1 realizes that he has indeed recommissioned the legendary Numbuh Zero (who is revealed to be none other than his own father) when the latter says he is hungry for blurpleberry ice cream, which is the closest taste he's had to the fourth flavor.
- Danny Phantom,
- In the episode "Splitting Images", Danny, while stuck in Poindexter's body in the Ghost Zone, contacts Sam and Tucker through the mirror in his locker to help him out. Since he looks like a green-eyed Poindexter, Sam tells him to prove his identity.Danny: In second grade, Tucker threw up in your lunchbox, but he told you Ricky Marsh did it.
Sam: [small gasp, angry] What?! I pushed him off the monkey bars for that! [points to Tucker] It was you?! [gasp of realization]
Sam and Tucker: Danny?
- "Parental Bonding" focuses on an amulet that turns whoever wears it into a dragon violently obsessed with getting what they want. For most of the episode, Alpha Bitch Paulina was the one wearing it, but towards the end, it ends up on Sam, which leads to this exchange:Danny: Take it easy, Paulina. You don't want to hurt Sam! (notices exactly who is in the dragon's claws) Paulina? (looks at the ghost dragon) Sam?!
Sam: SHALLOW GIRL!!!
Danny: Yep, that's Sam.
- In the episode "Splitting Images", Danny, while stuck in Poindexter's body in the Ghost Zone, contacts Sam and Tucker through the mirror in his locker to help him out. Since he looks like a green-eyed Poindexter, Sam tells him to prove his identity.
- Darkwing Duck:
- At the end of the two-part premiere, when Gosalyn thinks DW died, the next day she sees a man named Drake Mallard offering to adopt her. When attention is drawn to his severe injuries, he claims that he had an accident during breakfast because he "always forgets the milk," a reference to a convoluted training exercise he does in the morning as Darkwing Duck. This is when Gos realizes his Secret Identity and agrees to be adopted.
- NegaDuck once dressed up as Darkwing to fool SHUSH. Then he runs into the real Darkwing in the presence of others, but confuses them by anticipating and copying his reactions and words exactly in real time... until the original suggests there's something cute around, triggering an immediate Ax-Crazy Berserk Button reaction from his Evil Twin.
- Subverted in another episode where Darkwing infiltrates a prison after purposely being arrested wearing a rather lame disguise. At first, the four villains seem to see through it, but then Bushroot figures the real DW would be calling him "stupid names" like "Melon Head", so it can't be him. (Ironically, Bushroot is likely the most lucid of the four.)
- In The Fairly OddParents, in the episode "Twistory", George Washington is supplanted by Benedict Arnold in disguise. Timmy discovers who is the true Washington by describing how good the quality of the wood of a coat rack is; Benedict answers "So what?", but the real George Washington, who is obsessed with chopping anything made of wood, jumps and destroys the poor rack with an axe.Founding Fathers: [all in deadpan] That's Washington.
- Family Guy has a couple of weird subversions of this trope, which is of course appropriate for this show. Both occur is Season 9:
- "And Then There Were Fewer", the season opener, is a murder mystery that ends with Lois held at gunpoint by the killer, news reporter Diane Simmons. Peter walks in, completely oblivious as to what's going on, asking his wife where his Hot Wheels firetruck is. Lois, looking to tip Peter off by acting unconventionally, but not enough to tip off Simmons, refers to her husband as "Pete', something she's never done in their 20 years of marriage. Peter, being Peter, misses this completely.
- "German Guy" features a man calling himself "Franz Gutentag" posing as a puppeteer who turns out to be a former Nazi concentration camp official actually named Franz Schlechtnacht. Upon being discovered, Franz leads Peter and Chris to his basement to murder them. Chris takes the gun from Franz, but inexplicably faced with the dilemma as to whether or not he should shoot his father or Franz, questioning which one is his "real father", despite the fact that Peter and Franz look nothing alike. As a test, Chris asks them when is his birthday; when Peter (Chris' own father!) fails to give the correct answer but Franz does not, Chris shoots Peter, causing Franz to reclaim the gun retake the two as hostages.
- Inverted in an episode of Foster's Home for Imaginary Friends, Foster's Home is overrun with copies of Bloo after all of Mac's classmates thought Bloo was cool and thought up their own clones of him and donated them en masse to Foster's. Mac, however, wants to take Bloo to see the Ice Charades, but now he has to find the right one. A lot of them are easy to tell apart ("too tall, too short, too skinny, too aqua..."), but it comes down to two of them, and Mac goes through an entire Q and A with them before finally just saying "Alright, say something that proves you're the real Bloo." Bloo 1 gives an emotional, heartfelt speech about all the good times they had together. Mac notes it's something the real Bloo wouldn't say, and correctly deduces the real Bloo is the other one. And then every other Bloo clone ends up participating in the Ice Charades, leading Bloo to complain that Mac got the choice right because he gets to watch it instead of be in it.
- Parodied in the Futurama episode "Murder on the Planet Express", where Fry and Bender are trapped on a spaceship with a shapeshifting alien that disguises itself as someone familiar to the target to get close enough to eat them, so Fry and Bender question each other to determine if one of them is the shapeshifter—but neither can think of a good enough question.Fry: On your last birthday, what gift did I give you?
Bender: I don't remember.
Fry: Me neither.
Bender: Alright, I'll ask you one. What's the square root of 2,345.4?
Fry: ...That's not something I'd know.
Bender: Oh yeah. Your turn.
Fry: Um, what color is my shirt?
Bender: If I were the creature, I could just look at your shirt, dum-dum!
Fry: Good point.
- In the Garfield and Friends episode "Binky Goes Bad", Garfield reveals the real Binky the Clown by getting a judge to say "Order in the court!" The impostor says nothing, but the real Binky immediately responds with "I'll have a ham on rye, hold the mayo!" As the impostor is taken away by the police, Garfield comments that the real Binky could never resist an old joke like that.
- Eliza Maza identifies Talon as her transformed brother Derek when he automatically answers her "cross my heart" with "hope to die", complete with the particular series of gestures the two of them customarily use with the phrase.
- When Goliath is kidnapped by a shape shifter, Elisa comes to save him, and the shifter naturally takes her form. Since he and Elisa have been having trust issues the whole episode, Goliath tries to identify the real Eliza by shouting "Tell me the truth! Did you ever doubt me, even for a moment?" when Elisa sweetly replies, "Never!" Goliath knows that's the fake and tells his Minotaur cop-friend to shoot.
- G.I. Joe: Renegades: When Ripcord is revealed to be alive in "Prodigal", the Joes discuss the possibility that he's an imposter. Then, they run into an elevator full of unconscious guards and Snake Eyes.Ripcord: Ninja doorman. Me likey.
Duke, Scarlett, and Tunnel Rat: That's Ripcord.
- A variant of this trope appears in an episode of Goof Troop. Goofy and a double, who is a criminal, are in the same room, which Goofy had been wallpapering. Max identifies his father by leaving an open can of wallpaper glue in the middle of the floor and asking his dad to step forward. Both of them step forward, but only the real Goofy steps in the glue.
- On Gravity Falls, as Dipper and his friends are about to go into a secret bunker they discovered, he tells them that they have to keep whatever they find a secret; Wendy responds by making a zipping motion on her lips (like she did back in "The Inconveniencing"). Later, when they come across a Shapeshifting monster, it takes Wendy's form and the two wrestle on the ground. Dipper yells for the real Wendy to give him a sign that it's her; one of them winks, but the other makes the zipping motion, giving Dipper the clue he needed.
- Green Lantern: The Animated Series has a "Something Only They Can Do" variant in the episode "Prisoner of Sinestro". The titular prisoner is an alien assassin with the power to possess bodies, which he uses to try and off the Interceptor crew one by one. Later on, Hal realizes that the alien can't use their lantern rings since they can detect if it's really them or not, at which point Sinestro proceeds to purge the ship of oxygen so that the possessed lantern would be unable to survive without the help of the aura their ring provides and the assassin would be forced to go back to his original body in his cell, the only room in the ship with oxygen, or so Sinestro claims.
- In one episode of Inspector Gadget, Gadget and an imposter disguised as him storm into an awards ceremony being held by the Chief and many other police officers. Both try to convince the Chief that the other is the imposter, and the real Gadget, while doing so, accidentally clobbers the Chief over the head with one of his gadgets. The Chief groans, and tells the officers to arrest the other one, saying that the one who hurt him is obviously the real Gadget.
- In Iron Man: Armored Adventures episode "Heavy Mettle", Iron Man confronts Stane in the beginning of the episode telling him that he is done with his corruption and "manufactured evil." Later, Tony presents evidence to the Stark International Board that Stane made a deal with Ghost to get the designs for Iron Man's armor and Stane is fired. Before he is thrown out, Tony tells Stane that he and his "manufactured evil" are finished. This causes Stane, who was already growing suspicious of Tony, to realize that Tony Stark is Iron Man.
- Done at least twice in Jackie Chan Adventures. The first time, Jackie is split into an overly nice half and an asshole half, and when asked which is the evil one, Nice-Jackie dissolves into tears and proclaims that he must be the evil one because he accidentally stepped on a bug. Cue aside glances.
- The second time played it a little straighter with normal-Jackie fighting an evil clone. The good guys want to help but can't tell them apart. Captain Black asks them when his birthday is, and is dismayed when neither of them know the answer. Jade figures it out pretty quickly.Jade: Hey Jackie, will you take me to Moose World this weekend?
Clone Jackie: Of course-
Real Jackie: -not. You have homework.
Jade: (disappointed) There's your clone.
- The entire episode had a lot of this since each member of the J Team had an evil clone. Jade recognized that the Paco they had was a clone when he pronounced her name correctly; Paco pronounces her name as "Yade", due to Spanish being his primary language.
- The second time played it a little straighter with normal-Jackie fighting an evil clone. The good guys want to help but can't tell them apart. Captain Black asks them when his birthday is, and is dismayed when neither of them know the answer. Jade figures it out pretty quickly.
- In Johnny Test, Mr. Black and Mr. White make a robot clone of Johnny, and the others can't figure out which is the fake. Dukey figures it out when fake Johnny answers a math question very fast, since the real one always counts numbers with his fingers.
- In the The Legend of Zelda cartoon episode "Doppleganger", Ganon kidnaps Zelda after using a magic mirror to create a dark-clothed evil Zelda clone to replace her. Late in the episode, the real Zelda has freed herself and both versions end up covered in mud to the point where it's impossible to tell them apart. Link proposes a kissing contest to identify the fake. He rates the first Zelda's kiss as "very good," but gets a smack in the face instead of a kiss from the second ("*sigh* That's my Zelda all right.")
- In the Marvel's Rocket & Groot short, "Shapeshifter", in which Groot and Rocket chase a bounty who changes himself to look like Rocket. Groot uses this method to deduce who's the real Rocket:Left!Rocket: (calmly) I'm the real Rocket. Look, I know I don't tell you enough, but we've been through a lot. And I would never face the galaxy without you by my side.
(Groot is flattered and gestures to the Rocket on his right to speak his piece.)
Right!Rocket: (clears throat) YOU WOOD-FOR-BRAINS WASTE OF SPACE! I'M GONNA BUST YOUR BRANCHES IF YOU DON'T GET ME OUTTA HERE RIGHT NOW!!!
- Of course, the outburst from the second Rocket is what tips Groot off.
- My Little Pony: Friendship Is Magic:
- In the second part of the season two finale, Princess Cadence convinces Twilight Sparkle of her identity by reciting the song she and Twilight would sing when she foalsat her. Likewise earlier in the first part, the first sign that something's off about Cadence (She's actually Queen Chrysalis of the Changelings in disguise) is that she doesn't remember the song.
- Used by Starlight in the first part of "To Where and Back Again" to figure out who's real after a changeling invasion. Trixie repeats what she told Starlight earlier that day, Thorax transforms into Twilight and repeats her speech from "The Times They Are a Changeling", and Discord casually uses his chaos magic to transform their surroundings. Later, they come up with a two part password, where one person says "klutzy" which the other person must respond with "draconequus" so they can spot an imposter more easily in case they get separated.
- In Regular Show, Rigby hires Doug, a temp who eventually turns into Rigby. When Mordecai declares Doug the real Rigby, he asks for a hug. He then exposes that he knows Doug isn't really Rigby because he knows Rigby would never hug him.
- In The Spectacular Spider-Man, Venom/Eddie calls Peter "bro" to reveal who he really is.
- SpongeBob SquarePants:
- In the episode "Once Bitten", SpongeBob runs to the Krusty Krab to hide from the townspeople who are acting like zombies, but Mr. Krabs won't open the door because he thinks SpongeBob is a zombie. SpongeBob tries to prove he's not by slipping inside through the door cracks. Mr. Krabs is almost convinced, but when SpongeBob still pleads to be let inside, Mr. Krabs groans "That's SpongeBob alright."
- In "Whelk Attack", when Sandy wants to test if SpongeBob and Patrick are not whelks in disguise, Sandy asks SpongeBob what his mother's maiden name is and SpongeBob answers "BubbleBottom". Sandy asks Patrick what his first name is and Patrick doesn't know the answer.
- In Static Shock, this nearly ruins the title character's secret identity in "Brother-Sister Act". Early in the plot, Virgil remarks that his older sister Sharon is "totally Y2K", meaning old-fashioned or out-of-date. Later, when Sharon's watching Static's latest interview on the news, he uses the same phrase...and she realizes that no one else has ever used that slang before. She starts piecing together other clues and comes extremely close to figuring out the truth, even pointing out a Secret Identity Change Trick after Static defeats his latest foe ("you disappear, Static shows up. Static disappears, you show up!"). Thankfully, by some bizarre twist of fate, one of the Bang Babies in that episode is a little girl who can manipulate light to create realistic illusions, and she does Virgil a favor by conjuring an image of Static flying overhead while Sharon is standing right next to her brother. The trick works and Sharon is none the wiser.
- Steven Universe:
- "Giant Woman": Upon first meeting Opal, the fusion of Pearl and Amethyst, Steven gets a bit nervous upon realizing that Opal is very much her own person, and asks her if she knows who he is. Opal's response is to sing a bit of the song that Steven did earlier in the episode when he was trying to get Pearl and Amethyst to fuse thus proving she also has Pearl and Amethyst's memories and loves Steven as much as they do.
- "Familiar": Steven manages to accidentally convince the Pebbles, small creatures that live in the walls of the Diamonds' palace, that he's his mother Pink Diamond/Rose Quartz when he thanks them, as she was the only other person who did that.
- At the end of the Teen Titans season 4 finale we get this bit of dialogue:Beast Boy: Okay, you're freaking me out here! The white robe and smile are weird enough, but... hugs?!? Are you still...you?
Raven: Blue is still my favorite color, and don't get used to the smile because you're still not funny.
Beast Boy: Huh? [embraces her] RAVEN!
Raven: [looking slightly irritated] Quit it!
- Subverted in the VeggieTales episode "Princess and the Pop Star". Vanna, still dressed as Princess, tries to get her bodyguards to let her backstage:Vanna: Steve! Rusty! It's me, Vanna! You've got to let us in.
Steve: Hardy har har.
Rusty: Vanna Banana's inside, little girl. Besides, if you were the real Vanna, you would know our names.
Vanna: But I just called you Steve and Rusty.
Rusty: Right. But I'M Rusty, and HE'S Steve.
- Ultimate Spider-Man: "The Avenging Spider-Man" sees Loki swap bodies with Spidey and then later switch back to cause further confusion. Spidey turns to his SHIELD team for help, who still think he's Loki, until Nova gets close enough to him to smell him. Spidey had just traveled through the sewer to get to them, something Loki is far too arrogant to do.
- Invoked in the Wakfu sequel short The Quest for the Six Dofus Eliatropes. Yugo accused his brother Adamai of being a shapeshifter in disguise when the latter, convinced by Madame Shroud's words that to use them to rescue Sadlygrove, who had realised his power as the mortal incarnation of the god Iop, from dying at Ogrest's hands would result in the destruction of the world, refused to hand over one of the Dofus eggs to the former. Adamai was offended at the notion, and confirmed his identity by telling Yugo about the birthday gift they'd gotten for Alibert (Yugo's adoptive father), and about how Az (Yugo's pet Tofu and life-long friend) had recently begotten chicks.
- Wild West COW Boys Of Moo Mesa: Marshall Moo Montana got a letter from "Masked Bull" challenging him. He figured it was actually written by Horribull because nobody else called him "Meatball Head".
- In one episode of Xiaolin Showdown Omi has to watch Dojo, who is a risk due to a problem that occurs every few thousand years. Eventually, Dojo manages to fool him and escapes, leaving Omi in the cage. When the other monks return...
- Inverted in X-Men; Morph, Back from the Dead and evil, has taken the form of Wolverine, and Jubilee finds them circling each other. One Wolverine shouts that she should shoot them both, and so naturally she shoots the other Wolverine - the real one. It's even funnier because if she had just blasted both of them, the real Wolverine would have been protected by his Healing Factor.
- Young Justice:
- The way little Billy convinces the team (but mostly Wally) that he really is Captain Marvel is by mentioning how he shouldn't have to bring Kid Flash nachos and pineapple juice to get on his good side all the time.
- In the episode "Auld Acquaintances", Red Arrow is hiding from the mind-controlled Justice League when Aqualad finds him. To make sure he could trust Aqualad, he asks Aqualad "Who broke your heart?" To which Aqualad replies Tula... and Red Arrow himself, one of Aqualad's best friends, who was currently aiming an arrow at his chest the whole time.
- In the tie-in comic, the team is fighting Clayface, and Robin is confronted by two Wallys. Since Wally is the only one who knows Robin's Secret Identity, he asks for his middle name. At which point both are revealed to be Clayface.
Something Only They Would Say / Western Animation