So Much for Stealth

"It is a restful chapter in any book ... when somebody doesn't step on a dry twig and alarm [everyone] for two hundred yards around. Every time a person is in peril, and absolute silence is worth four dollars a minute, he is sure to step on a dry twig. There may be a hundred other handier things to step on, but that wouldn't satisfy Cooper. Cooper requires him to turn out and find a dry twig; and if he can't do it, go and borrow one."

- Mark Twain, The Further Literary Offenses of James Fenimore Cooper (Read here.)

We've got to get inside, but the place is crawling with guards. But no need to fight them! Using my amazing powers of stealth, we'll be in and back out before...

*crack of a dry twig*

...aw crap. So Much for Stealth.

In a situation where a character is trying to sneak around unnoticed, their attempt at stealth will suddenly be threatened by them stepping on a dry twig, sneezing, knocking something over, setting off an alarm, blowing their cover, or otherwise alerting others to their presence. If no one notices, they might be okay - in the worst case, they might be captured, or have to face the enemy in a full-blown battle. Either way, heads will turn suddenly.

Note that this trope often applies in situations where it would make no sense in real life for guards to be so super-sensitive, given the likelihood of the most startling noises being a Cat Scare. When considering what the hero is doing there in the first place, this falls Right Under Their Noses.

As a result, Genre Savvy sneaker-uppers will toss a stone so that it lands with a "plunk" in the direction opposite their position to make the guards go investigate -- see Throwing the Distraction. The guards, even seasoned Border Patrol, will always go for this old chestnut. If nobody notices when they really should have, see It's Probably Nothing and The Guards Must Be Crazy. If the attempt at stealth is laughably inept, see With Catlike Tread.

Anime and Manga

 * Stepping on a stick is how young Soujirou attracts the attention of Shishio in Rurouni Kenshin.
 * Case Closed: While in a supposedly haunted house, Conan accidentally knocks a broom over; he manages to keep it from making noise by catching it wit his foot, but not the bucket that fell along with it.
 * In One Piece, this happens thanks to a rooster... Sort of. Usopp, the one doing the sneaking, fully expects the rooster to crow and wake up the enemy, a government assassin capable of killing a hundred men single-handedly. Instead, the rooster quietly chirps, causing Usopp to scream in shock, "ROOSTERS DON'T MAKE THAT KIND OF SOUND!"
 * Happens to several characters in an episode of Hayate the Combat Butler, by stepping on game controllers of all things.
 * In Soul Eater, while Maka and Soul are trying to acquire the soul of Blair, they both hide behind a tree. Unfortunately, Soul's rear end is sticking out, and from there, Hilarity Ensues.
 * In To Aru Majutsu no Index, Touma tries to sneak up on the Skill-Out gang that has kidnapped Misuzu. Right before he can reach them, Misuzu herself sees him and gives him away. Touma screams, "Is she stupid!?" before he is forced to fight off the Skill-Out thugs.

Comic Books

 * In the Tintin book The Secret Of The Unicorn, Tintin is trying to escape the Bird brothers in their antique-filled basement. When he knocks over a big vase, he manages to stop it from falling, but the lid falls on a drum.

Film

 * Han Solo steps on a stick when he tries sneaking up on a Scout trooper in Return of the Jedi.
 * Mr. and Mrs. Smith:
 * Brad Pitt knocks over a stack of cans in the department store (but doesn't get caught).
 * Similarly, where both of them are trying to bomb each other out in their house, John accidentally knocks over a China pot, catching the pot but not on the end with the lid, which falls to the ground (cue John's Oh Crap face) and reveals where he is to his wife.
 * Ace Ventura: Ace sneaks into the mental hospital's storage room and accidentally steps on bubble wrap (but doesn't get caught).
 * Mocked in the Fistful Of Yen sketch of The Kentucky Fried Movie when the protagonist is sneaking in a dark room around the guard while knocking over various shelves, glass objects, and so on. The guard barely notices, sometimes looking as if he might have heard a curious sound.
 * In The Terminator, Sarah and Kyle are trying to escape the Terminator in a factory as Sarah accidentally presses a button, attracting the Terminator's attention.
 * On Toy Story 2, Woody tries to get his arm from Al, who is asleep on the couch. The first step he takes, he steps on a cheese puff, one of many strewn on the floor. Al doesn't wake up, so Woody goes ahead more carefully now, but then he hears another crunch, this time from Bullseye, who was following him. Again, Al doesn't wake up. Woody is about to get his arm when suddenly the TV turns on, waking up Al. Later we find out the TV was turned on on purpose by
 * In the first Toy Story, Woody and Buzz's attempt to sneak out of Sid's house is ruined when Woody's pull cord gets snagged and one of his recorded phrases wakes Angry Guard Dog Scud.
 * Cats Don't Dance: Danny and Pudge are secretly preparing things for the big number at the end of Darla's movie premiere. They accidentally bump into a drum set, but luckly they don't make that much noise and no one appears to notice. Then Pudge snaps his bowtie... and that is what alerts Battle Butler Max.
 * In the Riff Trax for Star Wars Episodes I and II, the riffers note that this really should happen to Qui-Gon ("How can you sneak around when you're six foot six?") and Anakin ("Hey, who's that up on the cliff? He's just bending over slightly." "Yeah, hi, we can see you!") - but naturally, it doesn't, since logic doesn't exist in these movies.
 * In Monsters, Inc., Mike's foot accidentally slips into a toilet when they're hiding from Randall. Subverted, in that Mike, Sully, and Boo barely avoid being seen.
 * In The Matrix, as the team is attempting to escape from the building by climbing down the wet-wall, one member accidentally kicks dust into Cypher's face, which causes him to sneeze, attracting the attention of a SWAT guy in the adjacent room.
 * Played wonderfully straight in the opening scene of Sleepy Hollow (1999), where we see the Hessian who later becomes the Headless Horseman escaping through the woods from Revolutionary War soldiers. He encounters two children gathering firewood and cautions them to silence with a finger to his lips. Without changing expression one of the girls deliberately snaps the stick she's holding, drawing the soldiers in their direction.
 * Mission Impossible. The famous "Mission Impossible" Cable Drop is completed successfully only for Franz Krieger to drop his knife -- it miraculously misses the alarmed floor and jams in the desk, dumbfounding the computer clerk when he returns to the room.
 * The Mechanic (2011). The two Career Killers infiltrate the penthouse of a cult leader and Make It Look Like an Accident. Unfortunately someone enters the room and finds the body before they've had time to resecure the mirror they unscrewed to crawl through – a nut drops to the floor, rolls along (they have their hands full holding up the mirror) and drops out a vent. A bodyguard goes to investigate and things get violent very quickly.
 * Hot Shots: Part Deux. Attempts to retrieve a keyring with a broom handle results in loud grinding of fan blades, knocking pepper into a sleeping guard's face, poking the broom handle up the guard's nose, and a radio switching on to loud music. The loud thump of the keys hitting the floor didn't wake the guard either. What did? A mouse, sneezing from the pepper, rouses him instantly.
 * Puss in Boots. Puss and Kitty manage to infiltrate a moving carriage well enough, then realise there's a whole litter of sleeping piglets in there. All goes well until Puss steps on a tail. So much for them boots...

Literature

 * Per the page quote above, Fenimore Cooper was uncommonly fond of having characters step on dry twigs in his books.
 * The Lord of the Rings: Wandering around the Mines of Moria, Pippin drops a stone down a well, alerting the enemy that someone is there.
 * Subverted in Magicians of Gor: Tarl throws a stone and the guy he's trying to draw away from his position turns towards him - he's Genre Savvy too.
 * In Edgar Rice Burroughs's A Princess of Mars, John Carter is slipping stealthily through a room full of sleeping Tharks when his weapons harness makes a small noise. For a moment it seems like nothing will happen, until a green warrior jumps to his feet and mayhem ensues.
 * In Graham McNeill's Warhammer 40000 Ultramarines novel Dead Sky, Black Sun, discussions of what to do in the Iron Warriors' fortress are rendered moot when the Nameless arrive and opt for immediate and noisy damage.
 * In L. Jagi Lamplighter's Prospero in Hell, Miranda realizes she is not alone when someone steps on a twig.
 * Happens in every other Honor Harrington battle. The usual line of dialogue is "That's torn it."
 * In the Dresden Files book Changes, Dresden's strike force was attempting to make a stealthy approach to Chichen Itza by way of the jungle. There's enough going on out there on a normal night that guards wouldn't automatically go ballistic at a twig, but then an escaped prisoner and a pursuing Red Court vampire run right into them. Things go downhill from there.

Live Action TV
"Benson: So much for the element of surprise."
 * In one of the season 3 episodes of Chuck, Chuck gets through a Laser Hallway, but then gets distracted and manages to bump into the system on the other side.
 * In one episode of Benson, Benson discovers a crime in progress. He happens to have a camera with him, so he takes a photo through a window. Unfortunately, the flash is on.


 * Cohen in the episode 'The Family Ties' of The OC. Ryan and he are trying to quietly enter the Cohen house - and fail at the car. Pretty much because of the fact, that Cohen is wasted. Stealth fails.
 * On a Top Gear episode that focused on finding the best car for a 17-year-old, one challenge was to see whose car could approach a house late at night with the least amount of noise (to avoid waking the parents). James May's car had a remote for the stereo and horn. Jeremy somehow got hold of it ...
 * Power Rangers Wild Force, "Forever Red" - On Earth's moon, Andros is spying on the last of the Machine Empire, who are busy unearthing Serpenterra. Seeing that they've almost finished digging it out, he turns to leave - and dislodges some rocks, sending them tumbling down the slope he was watching from. The robots give chase... on horses. Robots. Riding horses. On the moon.

Newspaper Comics

 * Parodied in a Far Side strip, in which some Indians are waiting in ambush, only for one of them to step on a bikehorn which someone left lying around.
 * "And you call yourself an Indian."

Video Games

 * The Genesis game ToeJam & Earl: when you tiptoe past a sleeping enemy you would occasionally sneeze and awaken it.
 * Can happen in the Metal Gear Solid games, if you're not careful.
 * Particuarly in the first game if you catch a cold  the random sneezing can attract nearby guards.
 * Uncharted forces you to do this at some point - you'll always be spotted when you enter an area with the enemies unaware.
 * Eternal Darkness has an enemy example. In one chapter you are being stalked by an invisible "vampire". While you can make it visible by casting a simple spell, if you don't have time you can tell where it is when it knocks some things over (particularly in the basement when you destroy it's source of power and kill it for real).
 * Said word-for-word by Barney Calhoun in Half-Life 2. He announces that your group will have to sneak through the building - then, as soon as he opens a door, a camera spots you.
 * In the Thief series, you can be given away if you move across surfaces made of metal, stone or anything else which makes a noise when you walk on it.
 * Can happen in Heavy Rain when Shelby's trying to sneak up on a robber. If you fail a Quick Time Event, Shelby will step on some potato chips and alert the robber.
 * In the Mass Effect 2 Kasumi DLC, you can accidentally set off the alarm clock while searching Hock's bedroom for DNA. The guards come running, but only if you snuck in instead of faking security clearance.
 * Happens so often to Faith in Mirror's Edge that sneaking is more like waiting to be spotted.
 * In Pokémon Black and White, Zorua and Zoroark have the ability to take on the appearance of other Pokémon in your party. And it can really work when battling another person... Until you use an attack that the Pokémon they're disguised as can't learn.
 * Scorch of Republic Commando will occasionally say this after an explosive charge is detonated.
 * Really can happen in any Stealth Based Game. If a guard notices you, or you trigger an alarm, it's usually time to either Save Scum or go guns blazing.
 * In World of Warcraft to prevent stealth runs (a party consisting entirely of druids and rogues using stealth to avoid all enemies but the bosses) certain enemies are fairly arbitrarily given the ability to see through stealth.
 * In Deus Ex Human Revolution, guards are often overly sensitive to sounds you make, even when the situation doesn't call for it. If there are footstep sounds from the bathroom, somehow they immediately know it's you and not a civilian worker or another guard tending to their business. It seems even more glaring given that they don't notice many things which are highly suspicious, like huge crates mysteriously moving around while they're not looking and their colleagues not showing up on their patrol.
 * Worms has an invisibility gadget that cloaks your entire team--but once a worm attacks, its position is revealed. Using Invisibility, then attacking, wastes the item.

Web Comics

 * Spoofed in an early instalment of Order of the Stick, where one of the heroes fails his Move Silently roll while the group is trying to sneak invisibly past a room full of guards -- and the noise that attracts the guards' attention is the sound of him saying "I GOT A FOUR! DID YOU HEAR ME? I GOT-!"
 * In a later strip, the group is trying to sneak into a bandit camp to save Elan (who rolled that 4), Belkar gets bored while someone else is trying to devise an effect stealth plan and just starts a fire instead, drawing the attention of every guard in the camp and getting the group caught.
 * Inverted in one of the first strips, when the entire group fails both spot and listen checks and ends up surrounded by goblin ninjas.
 * In Strays, how Meela notices Feral again. To be just, he did have reason to be distracted at the time.
 * In Goblin Hollow, one character botches a Move Silently roll, and his character trips. The guard turns out to be deaf as a post.
 * In The Specialists, what gives Hartmann away. Then, he did want to make contact with them.

Western Animation

 * In SpongeBob SquarePants SpongeBob is sneaking through Patrick's house, but every step he makes a very loud (and unrelated) noise. Fortunately even after he causes a ruckus Patrick is still asleep... until SpongeBob comments on what a heavy sleeper he must be.
 * In the Superman: The Animated Series episode "New Kids in Town", young Clark Kent is attempting to sneak around Brainiac, who's travelled back in time to kill him, however he knocks a rake over, attracting Brainiac's attention.
 * Family Guy parodies the above-mentioned Return of the Jedi example with Peter/Han stepping on a twig, a sheet of bubble wrap, a bike horn, a dog's tail and finally a radio.
 * Dr. Venture of The Venture Brothers has a moment like this when he accidently drops a lightbulb his bodyguard Brock Sampson asked him to unscrew for total darkness, thus alerting the nearby guards. After saying the trope name, Brock replies with an alternative plan: Throwing the Doctor into the group of incoming guards. Surprisingly, it works.

Other

 * Evil Overlord List #139: If I'm sitting in my camp, hear a twig snap, start to investigate, then encounter a small woodland creature, I will send out some scouts anyway just to be on the safe side. (If they disappear into the foliage, I will not send out another patrol; I will break out the napalm.)
 * Not really a Truth in Television. Most people (when they're acting as guard or something similar) won't react to the odd sound unless it's something that indicates a person is present (such as vocal sounds or the rhythm generated by footsteps). As a result, the sound of a snapping twig won't give someone away unless they're trying to avoid someone who's being very alert, or already knows that they're there.

Okay, guys, I think we managed that all right, now let's just sneak our way out of here and...

*crack*

... Dangit!