[[quoteright:214:[[Webcomic/{{Concerned}} http://static.tvtropes.org/pmwiki/pub/images/lethstu_219.png]]]]

->[[TheyKilledKennyAgain Once again]], Captain, your stupidity has doomed us all.
-->-- '''Marco, {{WesternAnimation/Sealab 2021}}'''

[[PunctuatedForEmphasis Don’t. Ever. Stay.]] around a Lethally Stupid character. Anywhere they go, havoc will go: properties will be destroyed, accidents will happen, people will die if they go near them. No matter how bad it gets. they won’t notice how dangerous they are.

This character accidently causes a disaster because of a stupid idea, didn’t think of the consequences, or because he/she made a terrible mistake. It is often PlayedForLaughs, because of the {{Slapstick}} and DarkHumor it may involve.

'''Golden rule:''' A Lethally Stupid character causes chaos by ACCIDENT. It’s never intentional. Because they don't realize they're at fault, they don’t learn from their mistakes, and so repeat them time and time again. Even if the character doesn't care about the harm he or she causes, the character may still qualify since intentionally harming others around them may not be the character's goal. The DamselScrappy, TheDitz, TheLoad, and TheScrappy are often this, because of the problems they cause. See also MikeNelsonDestroyerOfWorlds.

This trope is close to LethalKlutz, though a Lethally Stupid character doesn't have to be clumsy to cause disasters. Not to be confused with TooDumbToLive, when the character's stupidity gets ''himself'' killed (he might bring others down with him, but that's not a requirement). Also, Lethally Stupid may not always cause death, but they can make you want to kill them!

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!!Examples:

[[foldercontrol]]

[[folder:Anime and Manga]]
* Vegeta from ''Franchise/DragonBall'' has a dangerous amount of pride, as it has led to unleashing all three [[BigBad Big Bads]]. To sum up, Vegeta a) invited Frieza to transform, b) let Cell absorb 18 (even fighting his son Trunks in the process) and c) fought Goku fully knowing it would wake Majin Buu. Every time, a planet is threatened, and in the first and last case, one exploded (all three times if you count King Kai's). Not to mention he also died in the aforementioned first and last cases because of it.
** Goku also qualifies, since like Vegeta, he lets his most dangerous opponents transform to their strongest level of power even when the entire planet's at stake, and gave Cell a senzu bean right before he was about to engage in a fight to the death ''with his son''! In Goku's case, it's all for the sake of a [[GoodIsDumb fair]] and [[ChaoticGood challenging]] fight, although for both of them, this may all be because of their [[BloodKnight Saiyan]] [[InTheBlood blood]].
** Goten and Trunks aren't that bad on their own, but when they fuse into [[SmugSuper Gotenks]], all bets are off. Thanks to the rash decisions he makes in an attempt to make himself look cool, Gotenks unwittingly caused himself and Piccolo to get trapped in the Room of Spirit and Time, Super Buu to eat his friends and loved ones out of desperation, and allowed Super Buu to eventually absorb his power and give him an edge against Gohan.
** From before this, Pilaf releasing Demon King Piccolo in hopes of mooching off his conquest. Also a case of TooDumbToLive overlapping with EvilIsNotAToy.
* Many characters in ''Manga/RanmaOneHalf''. It's a miracle nobody dies onscreen.
* [[LawfulStupid Priscilla]] from {{Claymore}} caused her own awakening, and a shitstorm of epic proportions, this way. She insists on fighting [[StoryBreakerPower Teresa]] fairly, instead of delivering the BackStab as planned, or collaborating with her colleagues at all. End result: [[HorrorHunger the most dangerous]] [[HumanoidAbomination Awakened Being]] ever on the loose, and the 4 women most qualified to stop it (at that time; just flat out ever in Teresa's case) dead. [[DramaticIrony Also]], the former KnightTemplar devotee of the Organization is directly responsible for the death of a very large portion of the population they were [[spoiler:supposedly]] protecting and indirectly responsible for the Organization's own demise.
[[/folder]]

[[folder:Comics]]
* In ''ComicBook/TheWalkingDead'', Patricia frees a SerialKiller out of mercy, while he had already murdered two kids. It’s a miracle he didn’t get to kill anyone.
* In ''{{Tintin}}'', whenever Captain Haddock gets drunk, he ''will'' do something stupid and dangerous. Especially in the album of his introduction, where he gets Tintin into lots of trouble.
** In the movie, Haddock can be this while sober. He accidently hits a dam with a bazooka, causing a massive flood in a town.
** Pr. Calculus can be this to Haddock, who often gets AmusingInjuries from his clumsiness, inventions, or simply gets irritated by the deaf scientist who never hears what the Captain yells to him.
* ''ComicBook/GastonLagaffe''. It is the whole point of his stories. In French, “La gaffe” even means “the blunder”.
* Minor ''{{Popeye}}'' character Oscar veers into this trope at times. During the Eigth Sea arc, when Popeye's crew mutinies, Oscar's big idea is to sink the ship, thereby drowning the mutineers, and actually goes to it until Popeye tells him to knock it off and plug the holes. And later on, when the ship starts to sink because of a storm, he puts life preservers on the gold because "gold's harder to find than women". And in the Search for Pappy arc, when a man has fainted and needs water, Oscar just throws him into the sea.
[[/folder]]

[[folder:Fan Works]]
* In the ''Manga/DeathNote'' fanfic ''FanFic/MisaAndTheBear'', the taskforce is too busy watching daytime TV to notice a murder occuring across the street.
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[[folder:Films-Animated]]
* In ''WesternAnimation/FindingNemo'', Darla killed her last pet fish because she shook the bag too much. Did she learn from it? Nope, she does the same with Nemo.
* Scrat in the ''WesternAnimation/IceAge'' films. He caused the ice age, a volcano explosion, and the continental drift simply by planting an acorn. He also destroyed an Atlantisesque civilization because of his compulsive need to grab an acorn.
** Sid brings more problems than help to his friends. He is at his worst in the third movie, where he steals three dinosaur eggs, [[MamaBear which did not please their mommy]].
* In two films of ''Disney/WinnieThePooh'', Christopher Robin goes to school and leaves a message to tell his friends he’ll come back soon. Both times, Owl misreads the note and makes the others believe the boy has been kidnapped by a monster, sending them on a completely useless and dangerous quest.
[[/folder]]

[[folder:Films, Live-action]]
* Wherever Film/TheThreeStooges go, disasters are in the air. Just compare what the setting and characters looked like before and after these three showed up. Hell, in real life they'd be accidental mass murderers, and most likely dead a dozen times over.
* Creator/LaurelAndHardy. Especially Laurel! God, it’s a miracle Hardy stays alive around him. And in one movie… he doesn’t.
* Alan in ''TheHangover''. He is responsible for the events of both movies, but it is worse in the second since he uses the drugs again, not learning from his past misadventures.
** ''Film/DueDate'', from the same director and with the same actor, has a similar character, who spends the whole movie making {{The Protagonist}}’s life hell out of sheer stupidity.
* ''DumbAndDumber'': Lloyd and Harry. Especially Lloyd.
* In ''Franchise/DieHard'', the cops (excepting Al Powell) are so stupid and gullible they become threats to [=McClane=]. Especially in the first and fourth movie.
* JerryLewis always portrayed a character like this. Though, most of the time, he manages to look fairly likable.
* In ''Film/ScaryMovie'', many deaths are due to some characters being Lethally Stupid. In the fourth, the father keeps almost killing his daughter accidentally.
* ''Franchise/ThePinkPanther's'' Inspector Clouseau will either destroy your property, his own, make you insane, or cause your death. All this out of pure clumsiness.
-->'''Dreyfus''': Compared to Clouseau, this doomsday machine is just a water pistol.
* In ''Film/PlanetTerror'', during a zombie attack, a cop kills an old lady, thinking she was a zombie.
** Also, a doctor left a gun to her child, so he can protect himself. [[IJustShotMarvinInTheFace Less than half a minute after…]]
* In ''Film/PulpFiction'', [[IJustShotMarvinInTheFace Vincent can be dangerous even by accident]].
* In ''DinnerForSchmucks'', Barry's ''astonishing'' capacity for [[StopHelpingMe well-meant chaos]] takes up most of the plot.
* ''Film/TeamAmericaWorldPolice'': they save the world by blowing up everything in their path.
* Despite being scientists, the characters in ''Film/{{Prometheus}}'' repeatedly do stupid things that jeopardize their own mission. Two scientists get lost in a cave despite having maps with them (and one of them built the droids that made the map in the first place), one of the scientists removes his helmet to breathe the planet's air that could easily be contaminated, the scientists recover an alien head and then promptly cause it to explode, the main character informs nobody that she has given birth to an alien, which is now aboard the ship: the list goes on.
** David is somewhat exempt from this trope, as he sabotages some of the scientists and does rash things while exploring the planet because he's under orders to do so.
* Captain Hugh "Bullshot" Crummond in the film and stage play ''Bullshot''. Seriously, he's a walking disaster to exceed even Clouseau!
[[/folder]]

[[folder:Literature]]
* ''Franchise/HarryPotter'': Do you remember how often Hagrid put his pupils in danger by showing them creatures WAY too dangerous to study for kids? Or when he sent Harry and Ron to get help from Aragog? He doesn’t even seem to understand how [[strike:cruel]] hostile the creatures are.
* Adults in general in ''ASeriesOfUnfortunateEvents'' are [[AdultsAreUseless so stupid and oblivious]] that they leave the Baudelaires, other children, and themselves open to danger. ''Olaf'' [[VillainHasAPoint of all people]] [[LampshadeHanging lampshades]] this in the movie, showing how many problems they would solve by just listening to the heroes. This goes double for Poe.
* [[Literature/{{Twilight}} Bella Swan]]. Falling for a guy with all the hallmarks of a serial killer is just the start of it.
* ''OfMiceAndMen'': Lenny kills his pets and a woman accidentally, because of his great strength and little mind. This is PlayedForDrama, as he is actually mentally retarded.
* ''Literature/SpaceVoyages'': Bob Sandals, and UsefulNotes/{{NASA}} in general. Seriously, who sends three teenagers on a space mission launching at "the same time, just a couple miles apart" from another identical spacecraft piloted by two astronauts who [[TheDragon happen to be in the service of]] [[BigBad an evil alien emperor]]?
[[/folder]]

[[folder:Live-Action TV]]
* Steve Urkel in ''Series/FamilyMatters''. A boy genius who is still so clumsy and stupid, Carl is lucky to be alive and sane (most of the time).
* This the point of ''[[OneThousandWaysToDie 1000 Ways To Die]]'': many idiots are responsible for killing other idiots.
* ''Series/MrBean''. He never seriously hurts anyone, but still…
* In ''TheBigBangTheory'', Sheldon may be a genius, but is so self-centered and narcissic he doesn't realize or understand how much he annoys people. Many of his antics are caused by his social ineptitude, so often that it would be difficult to call Sheldon a mere {{Jerkass}}. He simply doesn't function like most people. Because of that, he is responsible for many catastrophes, and doesn't even see it most of the time.
** Leonard once made a dangerous experiment that resulted in the elevator being permanently broken. [[https://www.youtube.com/watch?v=nEx3FUvVp2Q Thanks to Sheldon, only the elevator suffered]]. That he saved all their lives (Leonard in particular) is implied to be the reason why the three other nerds put up with so much of his behavior.
* ''KenanAndKel'', and not only Kel. Few stories featuring these idiots end well.
* Kate in ''Series/RobinHood'', who has put herself in danger dozens of times, and gotten other people killed, because of her own stubbornness and stupidity.
* The plot of ''Series/MobCity'' is kicked off by Hecky Nash trying to blackmail Ben "Bugsy" Siegel with photographs that show Siegel killing a man. Hecky is so blinded by his hatred and contempt for the mobsters that he does not care that [[TooDumbToLive he is pretty much signing his own death warrant]] and that of everyone connected to the scheme. By the time the first season is over, almost everyone involved is dead [[spoiler:-- including Hecky and Siegel]].
* On ''Series/{{Justified}}'', the Crowes are a whole clan of StupidCrooks, but Dilly Crowe is particularly dimwitted. The family are running a profitable sugar smuggling operation which is low-key enough to keep them off the radar of any local or federal law enforcement. Even if caught, they will not be facing serious jail time for smuggling sugar. Dilly screws this up in a spectacular fashion. First he loses the family's profits gambling on dog races. In an effort to get back the money, he takes money that is supposed to be used to pay off a crooked Coast Guard officer and loses half of it in a casino. When the Coast Guard officer gets upset over this and starts mocking Dilly, Dilly shoots him. He single-handily turned a low-key smuggling operation into murder of a federal officer and brought the federal authorities right into their backyard. Now they are all looking at lengthy federal prison sentences. This is implied to be just one in a lengthy series of screw-ups that put the Crowe family in danger. Daryl Crowe manages to get the feds off their back, but it costs them their business and criminal connections. Fed up with Dilly constantly endangering the family, Daryl [[spoiler:has Dilly murdered]].
* StarTrekEnterprise was supposed to be about humanities first forays into exploration of space, which would necessarily involve them learning from their mistakes. Unfortunately, Captain Archer regularly makes mistakes even when the correct course of action is obvious or even explained to him.
** In ''Strange New World'', the Enterprise manages to find a previously unknown Earthlike planet. T'Pol (the Vulcan representative and science officer) says that standard Vulcan policy for examining a new planet is to perform surveys from orbit for a week before flying down. Archer says that those are Vulcan protocols, not Human. Human protocols, apparently, involve flying down to the planet right away and walking around without any safety gear. Needless to say this results in disaster. Furthermore, the technobabble explanation as to why the environment was bad for human biology is something that would have been picked up almost immediately, implying that absolutely no scanning at all was performed before they started breathing the air and ''drinking the water''.
** In ''Breaking The Ice'' Trip and Reed end up in danger when investigating a comet. The Enterprise cannot save them, but there is a more technologically advanced Vulcan ship nearby. Archers refusal to call them is not a "We must learn to not depend on the Vulcans" stance, but rather his refusal to ask for help from those [[FantasticRacism goddamn Vulcans]] as a point of [[HonorBeforeReason pride.]]
** In ''A Night in Sickbay'' the Enterprise has run out of spare parts for their warp engine. They need to get a replacement which will both help the ship run smoother, and ensure that they have enough spare parts to not get stranded in space. The Kreetassens have a spare part that is remarkably compatible with the Enterprise, however after Archers dog pees on their sacred trees, they kick them out and eventually demand a formal apology before diplomatic relations can continue. Archer is far more concerned that his dog caught a disease while on the planet. Even when T'Pol points out to him that he is acting far more concerned about the health of his pet than the safety of his ship (which his dog just so happens to live on) he still doesn't capitulate. While the Kreetassens are unreasonably uptight, they are also perfectly helpful once they are sincerely apologized to, providing an additional spare part beyond what they needed, making Archer look even more petulant by comparison.
** In ''Observer Effect'', Trip and Hoshi are infected with a lethal disease when they go literally digging through garbage without so much as wearing rubber gloves, or even using tools. The episode later confirms that an environmentally sealed suit would have protected them when Doctor Phlox is able to examine them without apparent risk while wearing a hazmat suit.
[[/folder]]

[[folder:Video Games]]
* Ben from ''VideoGame/TheWalkingDead'' is indirectly responsible for:
** The death of [[spoiler:Doug/Carley, Duck, ''and'' Katjaa,]] in Episode 3, [[spoiler:after the bandits force him to steal medicine for them. When Lee finds a bag of stolen medicine just outside the gate, he takes it to Lily, meaning the Bandits don't get the bag and attack. While the whole group manages to escape, Lily will either believe Carley to be the thief and shoot her, or believe Ben to be the thief and accidentally shoot Doug as he stops Ben getting shot. Later, Katjaa reveals Duck was bitten by a walker, and when he has to be [[MercyKill put down]], she commits suicide out of grief.]]
** The death of [[spoiler:Brie in Episode 4. While the group is trapped in an abandoned school due to hordes of Walkers outside, Kenny attempts to break through a door to a room believed to contain weapons. He sends Ben to find a tool to hack the door open, and he brings back a hatchet he found stuck in the handles of double doors leading outside. The hatchet was put there by Lee to stop the Walkers getting in. Brie gets killed when the Walkers break in.]]
[[/folder]]

[[folder:Web Original]]
* Many reviewers are this in ''Website/ThatGuyWithTheGlasses''.
* Lumpy in ''HappyTreeFriends''. You want to know how dangerous this moron is? He has a higher kill count than Flippy!
** Splendid causes more accidental deaths in "Breaking Wind" ''alone'' than Lumpy does over the entire course of the series.
** Pop's carelessness tends to be the reason for Cub's deaths.
** The Mole is a {{Justified}} example because of his blindness.
* Bronco and Silo, two students at SuperheroSchool Whateley Academy in the ''WhateleyUniverse''. Vamp's first exposure to them is when she is nearly hit with several hundred pounds of packed snow that get launched from the other side of a small hill and land on the sidewalk near her. This would have killed most of the students at the school. They are constantly getting detention for doing dumb stuff like this just because they can.
[[/folder]]

[[folder:Western Animation]]
* Dog from ''WesternAnimation/CatDog''. He wreaks so much havoc everywhere he goes any time he sees a garbage truck.
* ''WesternAnimation/EdEddNEddy'' cause chaos in the Cul de Sac, but never on purpose. Ed and Eddy, mainly.
* The Mayor in ''ThePowerPuffGirls''. He is far too incompetent for a crime-stricken place like Townsville, and can't do anything more useful than call the girls. And whenever he does something else, it's stupid and troublesome. In one episode, he even sold his town to Princess for candy!
** Big Billy is the least mean of the Gangreen Gang, but also the most destructive, because his strength is as huge as his idiocy.
* Goofy is generally portrayed as way too clumsy, but it gets worse in ''WesternAnimation/GoofTroop'', where his stupidity ends up putting [[TheChewToy Pete]] in dangerous situations extremely often, which was given special attention in "The Good, the Bad, and the Goofy", but in that episode, [[spoiler:Goofy ends up ''saving'' Pete]]. However, Pete usually brings Goofy into his schemes willingly.
* ''WesternAnimation/FamilyGuy''. Two words: Peter Griffin. He is so dangerously stupid he even got to burn down a children's hospital, by accident!
* Zapp Brannigan in ''{{Futurama}}''. Whenever he is called for help, he'll come to make things worse.
** Fry and Zoidberg are this too. Subverted with [[{{Jerkass}} Bender]].
* In ''JackieChanAdventures'', many episodes start when Jade causes troubles when toying with magic. She even accidentally shrank Jackie!
** And blew herself up... and duplicated herself... and knocked out Uncle one time. It's no wonder her older self recruits Uncle to produce the spells on her behalf.
*** And once nearly ascended to the level of Demon...(Though it saved the world in retrospect.)
* In ''WesternAnimation/{{Metalocalypse}}'', all the members of Dethklok are this. Every time they put on a show, it's likely to result in the violent deaths of their fans and other innocent victims, as the group tends to leave a trail of death and destruction anywhere they travel. Dethklok even requires fans who attend concerts to sign "pain waivers" that absolve the band of legal liability for these occurrences.
* Lightning Dust from ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' certainly qualifies. She is a flyer like Rainbow Dash. However, unlike Rainbow Dash, she is very reckless with her flying, unintentionally causing harm to the other flyers. Although she doesn't mean to cause harm, she doesn't care about the well-being of others and only cares about being #1.
** Rainbow Dash herself can be this at times. She's possibly the best flyer in Equestria, but her landings leave much to be desired, often smashing into things. Plus, there was that time she got it in her head it would be a good idea to kick a dragon in the face to get it to stop creating a smoke cloud over the country... and that was it.
** Derpy also qualifies, because as shown in "The Last Roundup," she causes unintentional damage to the town hall, which sets the whole plot in motion.
* ''WesternAnimation/TheSimpsons''': Homer Simpson is definitely not someone you’d want to see in a nuclear central. DependingOnTheWriter, Homer's stupidity can either cause merely property damages, or actually hurt people, and even make them insane (poor Frank Grimes...). In the Halloween episodes, he is often seen killing others because of his idiocy.
* Almost every adult in ''WesternAnimation/SouthPark'' is this, but Randy Marsh takes the cake. He even accidentally killed his daughter’s boyfriend!
* ''WesternAnimation/SpongeBobSquarePants''. Spongebob and Patrick. Really, these guys are freaking dangerous! Ask [[ChewToy Squidward]].
** Especially Patrick. Whenever he shows up in [[SeasonalRot newer episodes]], it's almost ''guaranteed'' [[DeusAngstMachina everything will go horribly wrong]], and [=SpongeBob=]'s relentless stupidity has also driven many people (mainly [[ButtMonkey Squidward]] and Mrs. Puff) borderline, if not completely insane. It's all mainly the result of {{Flanderization}}.
* Elmyra Duff of ''TinyToonAdventures'' will often leave a path of destruction behind trying to catch a "cuddly wuddly", and she also nearly kills her "pets" several times due to her stupidity; a Halloween episode took this further with several past pets committing suicide rather than having to deal with her.
* ''WesternAnimation/AmericanDad's'' Stan Smith veers to this with his self-serving ideas of what is right, and it doesn't help that he has access to dangerous CIA resources.
* Cosmo from ''TheFairlyOddparents'', not helped by the fact that he's magic. It takes a special kind of moron to sink Atlantis ''nine times''.
-->"[[OhCrap I know how to make it cleaner!]]"
* ''WesternAnimation/RegularShow'': Rigby tends to instigate life-threatening anomalies from simple, mundane subjects. Like unleashing a destructive video game monster when he was warned not to cross the wires.
* ''InvaderZim'', due to being very ChaoticStupid, such as accelerating the expansion of an explosion that had slowed down due to being in a time chamber. Even ''[[{{Cloudcuckoolander}} GIR]]'' points out how stupid that action was.
--> '''GIR''': But if it goes fast, won't it get all bad?
* Master Shake from ''AquaTeenHungerForce'', such as provoking the MonsterOfTheWeek or abusing one of Frylock's inventions, although it usually leads to his own demise.
* In ''FantasticFourWorldsGreatestHeroes'', Johnny causes some of their problems by burning something, or messing with Reed's stuff, and ends up unleashing a giant inter-dimensional insect.
* Billy of ''TheGrimAdventuresOfBillyAndMandy''. ''Everything'' he does will inevitably result in mass destruction and chaos, and if he gets his hands on magical weapons and artifacts such as Grim's scythe, you can bet he'll end up causing TheEndOfTheWorldAsWeKnowIt.
* [[WesternAnimation/TransformersPrime Miko Nakadai]], full stop. The girl has proven on ''multiple'' occasions that she simply cannot learn from her mistakes. Even after nearly getting herself killed (several times), nearly getting her friends killed (again, ''several'' times), and nearly getting some of the bots themselves killed ([[OverlyLongGag notice a pattern yet?]]). Miko still hasn't learned that she'd be of more help to the Autobots by ''not'' sneaking onto a battlefield and becoming a protective burden.
* [[WesternAnimation/TuffPuppy Dudley Puppy]] often accidentally inflicts AmusingInjuries on fellow agents, citizens, or bad guys. But especially [[TheChewToy Kitty Katswell]].
* WesternAnimation/InspectorGadget causes a great deal of harm to his superior Chief Quimby by always tossing the [[ThisPageWillSelfDestruct exploding message]] back at him. There are also times he somehow takes out Claw's minions by his own stupidity when his gadgets get out of hand.
* [[TeenageMutantNinjaTurtles2012 Michelangelo]] has been gradually becoming this. He often makes the mistake of goading monsters and mutation freaks which doesn't end well, and him screwing off near or with mutagen has resulted in several characters getting exposed to it, even himself at one point. And he still doesn't learn.
[[/folder]]

[[folder:Real Life]]
* Rowdy little children. In schools and at home, many children unintentionally wreak havoc and destroy things in their path, [[ItAmusedMe for the purpose of having fun]]. This is justified, as little children may not know wrong from right.
* Animals, especially common house pets like cats and dogs.
* People with mental disorders; they can cause harm to themselves or others and not realize it because their disorder prevents them from doing so.
* In regards to technological health; a script kiddie is considered more dangerous than a hacker because at least a hacker knows what he or she is doing. On the rare occassions that they don't, and manage to destroy something important by pure accident, a hacker usually has sufficient knowledge to fix whatever it was they broke, even if they have to resort to a scorched-earth format-and-reinstall.
[[/folder]]

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