Whether it is via the use of a Berserk Button or a Restraining Bolt, you know you can get a very precise reaction from a character if you do the right thing. Sometimes there's Animal Stereotype involved, but typically, it's according to the Rule of Funny or the Law of Disproportionate Response.
See also Damn You, Muscle Memory! for a real-life version, You Just Told Me for a related phenomenon, and Monster's Favorite Petting Spot. See Never Say That Again for a vocal version, and Won't Take "Yes" for an Answer for another. Compare Freudian Slip.
- There is a long list of things you shouldn't do if you want to survive a meeting with Golgo 13. Among them: do not touch his right hand, do not reach into your coat, and do not open a handbag. (He will attack at all of these.) His habit of standing when he meets a client comes from an early occasion where he killed a client's aide — the poor man made the mistake of walking up behind him while he was seated.
- Naru from Love Hina has a He Is Not My Boyfriend! reflex, whenever someone mentions Keitaro. She even does it after they're engaged.
- In Kenichi: The Mightiest Disciple, Miu was trained at a young age to automatically flip anyone who approaches her from behind.
- In Pokémon, Jessie and James's urge to say the motto can be triggered by anyone saying the words "prepare" and "trouble" in close succession. Try as they may to resist, they will blow their cover.
- A late XY episode had Pikachu electrocute them when Team Rocket ambushed him in a snowy forest. Team Rocket are just about to cry "We're blasting off again!" until they realize that Pikachu's shocks didn't have any juice to send them flying. They told Pikachu to try shocking them again, but it still isn't enough to send them off.
- Their rival Butch is on the receiving end of Accidental Misnaming so much that when someone identifies him correctly, he initially tries to correct them, before catching himself and realizing he didn't have to.
Butch: The name's Bu—! Oh, wait, that's what you said!
- Mallow's Bounsweet/Steenee's response to Rowlet getting close to her is to Rapid Spin it away with her leaves (likely due to an earlier incident where the owl mistook Bounsweet for an actual fruit). Unfortunately, this became part of a Disaster Dominoes in one episode that led to Rowlet and Popplio getting blown away in a bubble.
- Sgt. Frog: Keroro's natural showmanship gives him an irresistible need to run, slip and fall on any Banana Peel he sees.
- An old comedy sketch, made popular by The Three Stooges, had one man explaining to a stranger how his wife ran off with another man. Since he caught up with them at Niagara Falls, he goes berserk every time he hears those words...
- A similar sketch, performed by Abbott and Costello among others, involves a guy being roped into selling hats for the Susquehanna Hat Company. He goes up to various customers, trying to sell a hat, only to have them react in shock, horror and outrage at the mention of their name for various reasons ("my wife was wearing a Susquehanna hat when she died!", etc.). This happens several times, and when his last customer approaches him and asks him if he's selling Susquehanna hats, it doesn't end well.
- Even when enthralled by Dracula, the titular character (Xander turned into a teenage Xena) still immediately dives to the side upon hearing a Dramatic Gun Cock.
- Later Buffy automatically attacks an invisible person she senses during her meeting with Quentin Travers. It's only after the invisibility spell fails that she realizes he's a Council member. Fortunately, between her holding back and him wearing body armor, Buffy only badly bruised his ribs rather than driving them into his lungs. Later subverted when it's revealed she did it on purpose.
- In Mare Genius, when Pinkie tries to surprise Agatha with a Party Cannon, the latter's combat training automatically kicks in at what looks like a weapon being pointed at her.
- After their confrontation with the Slender Man in Don't Look, Misato and Shinji both have lethal responses to certain triggers for them. Misato will immediately shoot anyone she sees in a suit and Shinji will attack anyone who sneaks up on him with his box cutter. Only the other stopping them will halt their attack.
- Discussed in Dragon Knight when Willow wants to throw a surprise party for Buffy and plans to lead her to the party by telling her about a demon attack. Xander's wife Audrey points out that surprising a warrior after you've warned them about a deadly threat is guaranteed to invoke a lethal response.
- Jaune in Not this time, Fate has centuries of combat experience due to a "Groundhog Day" Loop. So when his sister leaps at him out of the bushes with a fake roar, he backhands her without even thinking.
- Shaggy the Handler: An old steam train's whistle sounds just similar enough to an incoming artillery shell to send the title character diving for cover, kicking off the plot of the second story in the trilogy.
- In Zootopia, Judy takes advantage of the wolves guarding Cliffside being vulnerable to howling. Once she starts howling the wolves cannot resist chiming in, allowing Judy and Nick to sneak past them.
- US Marshal Gerard exploits this in The Fugitive when he isn't 100% certain that he's spotted Richard Kimble, the titular character. So he calls out to him—"Richard!". Kimble involuntarily looks up, instantly giving himself away.
- In the original script Kimble actually manages to check this. He doesn't look up, but he does freeze in place for a few seconds before continuing down the stairs. The lack of response tips Gerard off just the same, especially since others in the stairwell display this trope by looking up.
- The Great Escape: Escape leader Bartlett and his second-in-command MacDonald are caught right because MacDonald instinctively replies in English to an English statement made by a German soldier, even though the pair is supposedly French (which is more than a little ironic because an earlier scene showed MacDonald warning another officer not to fall for that trick). This is Truth in Television; Roger Bushell (on whom the Bartlett character is heavily based) was caught because his traveling companion made a similar error.
- In Hangmen Also Die!, Czaka laughs at a joke told in German, revealing that he understands the language (not knowing German had cleared him of suspicions of betraying the Resistance previously). He unsuccessfully tries to pass it off as laughing at something else.
- In Abbott and Costello's Hold That Ghost, one of the heroines is being followed down the stairs by a man with a sheet over his head, who's miming her footsteps to hide his own. She gets suspicious, and taps out "shave and a haircut" with her feet and his cover is blown when he finishes with the "two bits."
- In Inception, Dom and Eames use this to find out where Dream!Saito has hidden his secrets. When they mention concealing secrets, Saito's eyes immediately flick towards a wall panel, behind which is a safe containing said secrets.
- Inglorious Basterds: Archie Hicox instinctively uses the English hand gesture to signal "Three", providing the final proof to a suspicious German officer that he's not who he's claiming to be. A lot of people die because one man raised three fingers instead of two fingers and a thumb.
- In Legally Blonde, the lawyer played by Luke Wilson confirms Elle's suspicion of a witness's homosexuality (he claimed to be having an affair with the defendant, a woman) by asking rapid fire, innocuous questions ("How long have you been working for the defendant? What was your job?" etc.) before ending with, "And your boyfriend's name is?" The witness answers reflexively, outing himself. His subsequent attempts at recanting are met with another young man standing up in the courtroom, angrily screaming "You bitch!" at him, and running out.
- The Tuxedo:
- The title tux always sends someone flying if they tap on its shoulder.
- And smoothly pulls out a lighter if someone puts an unlit cig in their mouth.
- Who Framed Roger Rabbit
- Inverted in an urban legend about the trial of a man accused of murdering his wife, though no body was found. The defense attorney said "You can't know she's dead. She could walk through that door right now!" and pointed with at the courtroom door with such energy that everyone in the room turned to look. The prosecuting attorney responded that he saw every head turned — except the defendant's. "He knew she wasn't going to walk in. He killed her."
- According to Himaruya, the author of Axis Powers Hetalia, a German army decided to bait out an Italian soldier by calling out a relatively common Italian name. The soldier with that name came out and said, "I'm here!" and the Germans got him. Later when the Italians decided to do it back to them, they had an Italian soldier yell out a common German name. The German soldier with that name came out and said, "Who called me?" "Me!" replied the Italian soldier. The German shot him right there. This joke in fact predates World War I.
- In the book The Wooden Horse, telling Mostly True Story of a WWII POW escape, the two British escapees are talking with Polish partisans trying to get aboard a ship leaving German territory. The partisans ask them a number of questions to ferret out if they are German spies, when one suddenly reaches out and slaps one of the escapees. His exclamation of "What the bloody!" in English is the final confirmation for them.
- In Men at Arms, Gaspode the wonder dog uses his ability to "speak human" on a pack of feral dogs by taking advantage of a Dog's instinct to obey a sharp human voice to SIT. In the air.
- In The Fifth Elephant, Vimes kills a werewolf by throwing a flare that the wolf instinctively tries to fetch. Ouch.
Earlier in the book, he determines that a character is more than they seem by their lack of a reflexive response to having an orange thrown at them. A fellow copper ducks, whereas this character, who is a trained Assassin, neither ducks nor attempts to catch the orange, but merely observes that the projectile isn't a threat and lets it harmlessly bounce off him.
- In an early Animorphs story, Jake ends up with a Yeerk in his head. The Yeerk manages to pass off as Jake for a while, but when Ax shows up in his Andalite body, the Yeerk can't keep a look af deep loathing from flashing across Jake's face, which Ax notices. When Ax suggests tying Jake up for three days (which would starve any Yeerk to death while leaving the host unharmed) and offers to morph into Jake to cover for him during this time, the Yeerk hysterically snaps when Ax goes to touch Jake to absorb his DNA and calls him "Andalite filth!" out loud, which naturally is the last proof the rest of the gang need to know that Ax is right.
- In Friends, Phoebe uses this as a game to help people make decisions, asking them a series of unrelated questions until hitting them with the choice they've been struggling with. Ross later uses this to work out why Phoebe is mad at him (she dreamt that he insulted her), and it lands Chandler in hot water with Joey when he reflexively reveals that he doesn't think the movie Joey's been cast in will be his big break, contrary to his supportive words earlier in the episode.
- Ross and Rachel teach Chandler to learn a series of reflexive responses to questions his girlfriend might ask ("Does this make me look fat?", "Is she prettier than me?" etc) in order to avoid arguments.
- Agent 99 of Get Smart instinctively judo throws anyone who sneaks up behind her. She also does it when she attempts to explain this.
- In season 6 of How I Met Your Mother, when Lily announces that she is pregnant, Barney immediately screams "I've never slept with that woman before in my life!"
- In an episode of Full House, DJ gives her father a very mature and well thought out presentation on why she should have her own room. Danny asks for a few minutes to think it over, then tells her he's made his decision. DJ immediately yelps, "Dad, that is completely unfair!" A perplexed Danny tells her he hasn't even said anything yet, at which point a sheepish DJ admits that it's "force of habit". Apparently, years of watching her father take her younger sisters' side over hers had conditioned her reaction — indeed, she's downright stunned when Danny agrees with her.
- In an episode of Sherlock, "A Scandal in Belgravia", Sherlock is looking for Irene Adler's cell phone, which has incriminating pictures on it. While he talks to her, John steps outside and lights a magazine on fire, triggering the smoke alarm. When Irene hears the alarm, she instinctively looks at a mirror on the wall that conceals a hidden safe, pointing Sherlock directly to the phone.
- In one "Weekend Update" sketch from Saturday Night Live, Jimmy Fallon believes that Tina Fey is about to tell the viewers that he has a small penis, and suckerpunches her in the face. She asks if his paranoia is proof that it's true, and he hits her again. She then blurts out "small penis" and gets hit yet again. When she glares at him, he giggles nervously and explains that "It's an instinct."
- On QI, this is one way the producers trip up the contestants in the General Ignorance round (where giving the obvious answer is usually the incorrect one and will cost points).
- On WKRP in Cincinnati Les rewrote the station's emergency handbook so that it only covers Soviet invasions. When a tornado hits Cincinnati he's forced to improvise by reading it on the air and replacing the word "communist" with "tornado," so he urges Cincinnatians to stand up to the "godless tornados."
- Law & Order: UK. Detectives Brooks and Devlin have arrived at a junkyard to look for a murder suspect. When they're told the man in question isn't there, they suspect otherwise. Devlin casually calls out, "Oi, Freddy!". Sure enough, Freddy looks up at the sound of his name, then further confirms his identity by bolting when he sees the cops.
- Stargate SG-1, when SG-1 accidentally time travels to The '60s, they are captured on the suspicion of being Soviet spies. When one of them asks in Russian if they're Russian spies. Daniel, being a linguist, instinctively answers "no"... also in Russian.
- Garrett does this on Superstore when he's DJing at Cheyenne's wedding to Beau. After making an announcement to the crowd, he follows up with "Thank you for shopping at Cloud 9. Dammit. Force of habit."
- In the season 1 finale of Jack Ryan, Jack is chasing the Big Bad into a crowded train station. Not seeing him, he shouts "I have your son" in Arabic. The terrorist spins around to look at him, revealing himself to Jack.
- An early encounter in Improbable Island is with a professional romance writer, who you involuntarily punch the instant she says so. She takes it in good stride, surprisingly, mentioning that she seems to get that reaction from everyone she meets, directly suggesting that it must be a conditioned response. What starts the obligatory fight is when you utter the phrase "professional romance writer", and she has the same reaction. Much later, you learn that even the sneaky bastard lion can't resist this impulse.
- In Senran Kagura, even Shinobi trainees are at risk of being attacked by rivals while going about their business in public spaces, so one of their first conditioned reflexes is to pull their primary weapon and smack an enemy who gets within arm's reach without thinking about it. This is why Peach Beach Splash permits bladed weapons and brutal punches as melee attacks in an explicitly bloodless water-gun tournament, the reflex to use weapons at close range is too powerful to be outlawed.
- Team Fortress 2:
- Many Scouts have it drilled into themselves that a Scout standing still is a dead Scout because of his Fragile Speedster status. But it makes it hard for allies to try and heal him or extinguish any fire on him.
- It's usually best to steer clear of a Pyro lest you get caught in their flames and die a fiery death. But when you're a Spy and disguised as an enemy player, being too cautious around other Pyros can give the disguise away and mark you for a spycheck very quickly.
- When you're approached by someone brandishing a melee weapon, it's instinctive to keep your distance while you still have ranged ammo. This works to the favor of a Heavy with the Fists of Steel, as the weapon gives them resistance to ranged weapon damage but raises their melee damage vulnerability.
- Since the very beginning, World of Warcraft features damage zones, glowing circles of poison, fire, darkness, whatever. The message ingrained into every competent player's head is that if a glowing circle appeared under you, move out of it immediately or die. In the Cataclysm expansion they give several healing classes an area of effect, over time heal that took the form of... a glowing circle on the ground. Unsurprisingly, everyone is having to fight the urge to move out them. It's probably worst for druids; while shamans have blue and priests have yellow, neither of which is a common boss damage circle color, druids' circles are green, and thus resemble a cloud of poison.
- In a Shadowrun sourcebook, iconic character, Hatchetman, is telling of his slow evolution from street punk to cyber samurai. At one point, he comments on how he used to snicker at older streetsams who would normally stand with their backs to the wall for being paranoid, only to get the "wired reflexes" mods himself, and finding himself doing the same thing to keep himself from reflexively striking somebody coming up behind him. He isn't paranoid of being hurt, but of hurting an innocent.
- Felicity from the webcomic The Dreamland Chronicles has to steal anything sparkly, no matter what sort of life and death situation the protagonists might be in at the time and how ill-advised stealing the glowing magical pendent hovering in mid-air might be. It's surprising that she's not an anthromorphic ferret or magpie, but rather a cat.
- Dark Smoke Puncher in The Adventures of Dr. McNinja is pulled over by a cop, who asks "Son, do you know what I'm stopping you for?", and DSP instantly continues the line from "99 Problems". The Alt Text confirms that it's like Roger Rabbit with "Two Bits".
- Freefall: "BALL!", "DOGGY!", "FRISBEE!"
- Keychain of Creation: The Solar Exalted of the First Age developed many means to control their Lunar partners.
- In one strip from Girl Genius, Agatha humiliates Krosp the genius uplifted cat by showing that he still has a hair-triggered kill-response to a dangling piece of string.
- The Order of the Stick: Haley gets to play with Tarquin's arrow-catching reflexes by firing two arrows toward his head while he's hanging on the railing of the Mechane. He does snatch both out of instinct, but doing so makes him lose his grip on the side of the ship.
- In the Green Lantern episode of Duck Dodgers, when Dodgers actually agrees to Sinestro's hero-villain seduction speech, Sinestro goes on to call him a fool for rejecting before realizing that this time, someone actually said yes.
- In one episode of Bonkers a toon criminal forces Bonkers to activate a deathtrap by placing a "Do Not Press This Button" sign on the activation button. As a toon, Bonkers is incapable of resisting a temptation like that.
- In an episode of The Simpsons, where Lisa is doing something bad for a change:
Marge: Bart, nooooo!
Bart: [standing right beside her] What?!
Marge: Sorry, force of habit. Lisa, nooooo!
- American Dad! has a similar joke in an earlier episode, where Steve gets impregnated by Roger. When Stan finds out, his immediate response is to yell at Hayley for "tarting around town". She angrily points out that she didn't do anything, and Stan says that he always assumed this would happen to Hayley, so it's what he's prepared for.
- In "Four Little Words", Bullock accidentally kills his new girlfriend when she playfully sneaks up on him from behind, causing his CIA training to kick in and make him snap her neck without even turning around.
- In "Lincoln Lover", when Stan and Steve go to a Republican convention, every visitor must pass the "gay check". This usually includes things that look for this trope, such as asking the visitor to look at his nails (according to Stan, a "real man" does it palm up, while bending fingers, while a homosexual does is the feminine way - palm down and stretching out the fingers), asking what "ERA" stands for (once again, a "real man" would say "earned run average", a baseball term, while a homosexual would say "Equal Rights Amendment"), or saying a few words from a musical (a homosexual would sing the rest).
Guard: [monotone] Clang, clang, clang.
Visitor: [cheerfully singing, as if on stage] Went the trolley! [being carried off by guards] No, I just like musicals!
- Tom and Jerry: Tom has used a dog's urge to fetch to get Spike off his back, only to come across the problem that once a dog starts fetching, they won't stop.
- Bugs Bunny and Daffy Duck has pulled the fetch stunt on a few hunting dogs a few times during their career as well.
- Chip 'n Dale: Rescue Rangers: Monterey Jack's Follow Your Nose reactions upon smelling cheese.
- Family Guy characters know Brian can't resist fetching objects.
- Steven Universe: In "Mindful Education", Connie instinctively flips a student that bumped into her due to her months of training with the Crystal Gems. Once she realizes that she just injured an innocent person for no reason, Connie is completely mortified and runs off in fear and shame.
- The studies of Ivan Pavlov have become famous for demonstrating this in dogs. He would ring a bell every time that food was served to the dogs, and eventually the sound of the bell would connect instantly to the idea of food being brought; hence, when he rang the bell, the dogs would salivate more and expect the food to be brought out even if there wasn't any.
- Some torturers have been known to use Coca-Cola bottles to beat or sodomize victims, because they know that the Coca-Cola franchise is one of the most prevalent in the world. Even if their victim is released, they will be confronted with reminders of their terrible torture forever onward through advertising.
- The ever-popular "Check her out!" "Who, where?" Especially funny when the person being baited is married and/or in a serious relationship, and his wife/girlfriend is right there, forcing him to backpedal. "Whoever she is, she can't be as pretty as you are!" or "Who cares, I have the most beautiful woman in the world right here!"
- Most every bicycle in Japan has a bell to warn pedestrians that someone is rapidly approaching, at which point the walking pedestrian, used to the sheer amount of cyclists in the nation, will move to the side. One YouTuber invoked this by carrying around a bell as he walked, and rang it to part the seas of crowds. Instinctively, many moved to the side without even bothering to look back.
- A surprising real life example: Once, when police were entering a house to look for a burglar, one of them said "Marco" in order to inject some humor into the situation. The burglar said "Polo" and was promptly caught.
- Two men were on trial for burglary, and a possible witness was on the stand. The prosecutor, leading up to asking her to identify the people she had seen entering the house, asked, "Are the men who broke into the house in the court room here today?" The defendants raised their hands.
- Apparently, during World War 2, it was possible to ferret out German infiltrators among Allied prisoners of war by randomly shouting "Achtung!" and seeing who reacted by reflexively coming to attention.
- As mentioned in the film section, this is how Roger Bushell, the man behind the real "Great Escape", was captured. Like his counterpart in the film, Bushell and his companion, Bernard Scheidhauer, were posing as French businessman. They initially passed the checkpoint, but as they were walking away, a guard turned and abruptly fired off a question in English. Scheidhauer, who was French by birth but had become accustomed to speaking English with his fellow POWs, reflexively answered the question in English.
- A German comedian, Jonny Buchardt, in 1973 led an audience in several cheers and slipped in a "Sieg!" The audience members that were adults during Nazi Germany responded with "Heil!", much to his disbelief.
- For your own safety, it might be best to avoid startling an ex-soldier.