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* ''TabletopGame/BattleTech'':
** Clan Ice Hellion historically had a bad habit of rushing into situations without thinking. This resulted in them being one of the weakest of the Clans and they were derided by their fellows as "Clan Tantrum". However they only truly hit this trope when they tried to invade the Inner Sphere on their own; something that ''seven'' vastly superior Clans had (at best) limited success with. They were promptly ripped apart before they even reached the Inner Sphere as they ran straight into the Occupation Zone of the much stronger Jade Falcon and while fighting them decided [[ChronicBackstabbingDisorder it was a good time to double-cross their temporary allies]], Clan Hell's Horses. This ended with them getting [[CurbStompBattle utterly trounced]] in a brutal war on two fronts, with the few survivors being forced to join another Clan in order to avoid being [[KillThemAll completely killed off]].
** Clan Smoke Jaguar, [[KlingonScientistsGetNoRespect with their over-emphasis on the Warrior caste and completely ignorant eschewal of their Scientist, Technician, Worker, and Merchant castes]], also qualifies. They decided that as warriors, they have no need for common necessities like basic logistics and producing their own wares for both their civilian and military castes, and chose to raid other people's territories for their resources. This way of thinking resulted in the most fatalistic depiction of CripplingOverspecialization ever and it cost them big time when they participated in the Invasion of the Inner Sphere. Additionally, their personnel suffered from poor discipline and lack of charisma and their way of settling conflicts with others is to go head on berserk charges towards their opponents with little to no heed of tactical or strategical planning whatsoever, similar to their Ice Hellion counterparts. All this came to a head when the Jaguars thought it was permissible to lay [=WMDs=] and OrbitalBombardment of certain strongholds they came across, eventually leading to the Turtle Bay Massacre. [[GodzillaThreshold Not only did this drew the collective ire of just about every Inner Sphere faction who were busy fending off the Clans]], but the other Clans thought it was [[EvenEvilHasStandards too much of a line to cross]] and effectively cut off all support for the Jaguars. Eventually the Jaguars were [[KilledOffForReal annihilated for good]] several years later by a combined Inner Sphere and mercenary unit assault while the other Clans stood by and did nothing.
* ''TabletopGame/DungeonsAndDragons'': The [[EvilHand Hand of Vecna]] is an ArtifactOfDoom that requires its user to cut off his or her own hand/eye (there's also an eye of Vecna) and graft Vecna's in its place. The artifact grants its user magical power, but has a mind of its own and wants the user to follow its agenda. The hand can kill those who disobey. And those who obey, too! So, you're pretty much screwed either way.
** Also, as the [[ComicStrip/KnightsOfTheDinnerTable Knights]] remind us, there can be some who don't remember that the Hand of Vecna is a LEFT hand when it's time to do the lopping.
** There's also the decidedly ''non''-canonical [[http://www.blindpanic.com/humor/vecna.htm Head of Vecna]], which induced TooDumbToLive on an entire ''party'' in a CrowningMomentOfFunny. (Of course, maybe it's just as well this thing was just a joke. Given what Vecna's Hand and Eye have been known to do to folks who use them, just imagine what his ''brain'' could do.)
*** In some tellings, the killings only stop when one of the party notices the head [[CriticalResearchFailure has both eyes.]]
** But let's be fair: the Hand and Eye could just as easily be grafted onto somebody who already just ''happens'' to be [[HandicappedBadass missing a left hand and an eye.]] Provided they don't know the full and terrible [[SealedEvilInACan history]] of the items, they might be classed as tragically stupid instead of ''hilariously'' stupid.
* ''Racial Holy War''. The "holy white warriors" you roleplay are, put bluntly, so dumb they can be wielding an assault rifle and ''still'' be chased off by a horde of Jewish babies and grandmothers (and not {{Badass Grandma}}s either).
** They'll also accept bribes not to fight in the middle of combat. It gets to the point that people sometimes wonder if it isn't actually a StealthParody.
* In ''TabletopGame/{{Rifts}}'' there are aliens called the Arkhon, a race of (not proud) warriors. One particular clan has lost favor, and decides to redeem themselves by invading Earth. The reasoning behind this is that the Arkhons had attempted an invasion on Earth a few thousand years ago, and had gotten utterly routed by the magic of the Nazcan Empire. Basically, the plan was to go to a planet that had proven itself to be more than a match for them when said race thought bronze was the height of technology, and has presumably been advancing steadily ever since then, and try and take it over. Even ignoring the fact that the Arkhons didn't know about the [[CrapsackWorld insanity]] that had happening on Earth over the last few hundred years, the Arkhons were more or less committing very elaborate suicide. You'd think they would have stopped and reassessed their plans when they lost a third of their fleet en route, and then lost another quarter of their ships when the orbital community attacked them.
* ''TabletopGame/{{Toon}}'', being essentially ''[[WesternAnimation/LooneyTunes Looney: the Tunening]]'', has a significant rule that if you fail a Smarts check in the right circumstances, you will be too dumb to ''die''. You can be on the bottom of an ocean strapped to an anvil, but [[AchievementsInIgnorance if you don't realise you can't breathe underwater, you won't drown]]. And even if you don't survive, what of it? [[DeathIsCheap You'll be back in three minutes anyway.]]
* ''TabletopGame/{{Warhammer}}''
** Generally anyone who sells their soul: a boost, albeit a very large one, in one's abilities does not justify becoming a monster. Also note the parents who give their mutant children to Beastmen in ''Warhammer Fantasy'', yes it is understandable as the child would be killed otherwise, but it is stupid because these children have a habit of coming back with beastmen during a raid, then killing and feasting upon their own parents.
** And the dwarves. Oh boy, the dwarves. They take RevengeBeforeReason to the point where it's firmly in TooDumbToLive territory. They're all fanatically bound to a code of personal honour that holds vengeance as a ''sacrament''; no matter how trivial the slight or minor the offence, they never forgive and never forget. They actually have a big book where they hold all the grudges they have against the other races, and try to resolve these grudges with big battles. Win or lose, they take the casualties of those battles and put ''them'' down in the Book of Grudges as well, to avenge later. As a consequence, they are pretty much constantly in a state of war with everyone and are rapidly dying out. Natural selection at work.
** Declaring a constant war on the most powerful mages in the world, and the most skilled warriors (Elves, even if they are dying out), the most numerous enemies (Orcs), the most high tech (Skaven), the toughest soldiers (Chaos) probably do not help the dwarves chance of lasting longer than a few years.
*** The Dwarven Slayers (Troll Slayers and Giant Slayers) take this trope to UpToEleven. Justified since they're [[DeathSeeker Death Seekers]].
*** Becoming a submarine sailor is an alternative career for a Dwarf who would otherwise become a Slayer. Dwarves have a notorious fear of seas.
** The absolutely [[AxCrazy mad]] vampire Konrad von Carstein, although it is probably more of an example of being Too ''Insane'' to Live. This is the kind of guy who convicts his own mother for the crime of giving birth to him without his own permission.
** Bretonnian Knights Errant. Those HotBlood young knights are impetuous - i.e. they will spontaneously attack any enemy at reach unless they pass the Leadership check, and they are Immune to Psychology on the turn they charge. The usual result is a SuicideAttack. This tendency acts also as a kind of a Darwinist natural selection - those Knights Errants who survive, are to become the new Knights of the Realm.
** Snotlings are not only stupid enough to make [[Main/OurOrcsAreDifferent Orcs]] look like [[Main/GentlemanAndAScholar warrior scholars]], they also tend to imitate the behaviour of other units nearby. If they for example see veteran Black Orcs charging a giant monster, they will happily do so as well, despite their small size and feeble combat skills. No wonder other greenskins think of them primarily as emergency rations.
** The Elves got their moments too. Wanna know why the War of the Beard is called that? Meet Caledor II the Warrior, the Phoenix King at the time of that war. Long story short, Dark Elves disguised as High Elves attacked a Dwarf caravan. Gotrek, the Dwarven High King, demanded explanation and recompense. Caledor replied [[{{Arrogance}} that he would only answer to pleas, not to demands, and sent the Dwarf emissaries away with nothing]]. This would propably be enough for the Dwarves to start a war, but Gotrek sent the emisaries again. This time the emisaries refused to return with nothing saying they'd rather have their beards shaved off (a GRAND insult for a dwarf). Caledor [[WhatAnIdiot did just that]]. And so began a war that ended with both races on the verge of annihilation, Caledor dead, and the prized Phoenix Crown in the hands of the dwarves. There are differences in this story between elves and dwarves but both agree that Caledor, rather than being called Caledor the Warrior, should be called Caledor the Idiot.
** The crowner, even worse than Caledor II, has to be this one Imperial lord in the fluff who one day decided it would be a good idea to hire [[AlwaysChaoticEvil the Skaven]] to be deniable asset mercenaries in his political games. This alone is enough to qualify, but then he decided it would also be a good idea to ''try and back out of his side of the deal''.
* ''TabletopGame/{{Warhammer 40000}}'':
** Being Too Dumb to Live is epidemic almost to the point of an actual infectious disease. The Imperium is the most common offender (having among other things ignorance and blind fanaticism to government policy might be a reason for that) but by far the worst are any and all servants of Chaos, a faction that performs regular human sacrifices for anything more complicated than boiling water and is engaged in a perpetual EnemyCivilWar due to being, well, ''{{Chao|ticEvil}}s'', yet they still have a constant stream of followers willing to embrace madness and slaughter for the miniscule probability of achieving the "honour" of daemonic possession.
** While we're on the subject of the Imperium, the Imperial Infantryman's Uplifting Primer. Whoever wrote it seems to have been a lobotomized imbecile with no military, tactical, or mechanical experience whatsoever, assigning hymns to everything such as loading a lasgun or autopistol and throwing a grenade which we all know is bullshit (and the Litany of Stealth, to be recited as you approach the enemy), encourages Leeroy Jenkins tactics, tells soldiers they will die horribly, gives disturbingly awful background information on enemies, giving gems such as: "Ork weapons are extremely crude and prone to misfires or jamming." [[note]] Maybe true for the shootas and any other ranged weapons, but as the [[Literature/CiaphasCain HERO OF THE IMPERIUM]] points out, they're effective as the average bolter. And I did see an axe misfire [[NoodleIncident once]], but it really wasn't all that likely. Impossible under any circumstances, really.[[/note]] "Tyranid weapons are formed of living tissues,[[note]]True.[[/note]] they often fall apart." [[note]]''Not'' true without some major application of firepower.[[/note]] "Eldar technology is antiquated,[[note]]Technically, true.[[/note]] Eldar craftsmanship is inferior to our own."[[note]]Haha, no.[[/note]] "Beware the tau - they'll sacrifice your babies to their gods!"[[note]]Nyet--Tau are {{Flat Earth Atheist}}s to the point of ScaryDogmaticAliens.[[/note]] It also says Tau are frightened by fire. And water. And thunder. And unnerved by hairy people [[note]] Were that true, the Imperium could just send in the Space Wolves and maybe some Valhallans.[[/note]] [[BlatantLies They are also derived from bovines and chew cud and have udders. They have terrible eyesight so that their hearing overcompensates, allowing you to scare them off with loud shouting. And those guns they're carrying require sustained streams to injure a healthy, armored human]][[note]]bullshit, bullshit, and groxshit. First one is racist. Second is half-true. The tau have worse eyesight and more sensitive hearing than most other races, but they compensate for the first with hard training and extremely good targeting aids, and the second is only really relevant when it comes to noise on the level of sonic weapons, and they do a number on anyone. Third is lethal groxshit-Tau guns are some of the most powerful in the game, being very capable of knocking over a SpaceMarine.[[/note]] Then, somewhere else in there, it says that Imperial soldiers have the best armor and weapons, which will oneshot anything and protect from anything[[note]] So a glorified t-shirt and flashlight is a better choice than power armor, a [[ChainsawGood chainsaw]] and bolter? [[http://www.youtube.com/watch?v=SCh0BXdVtmE Ah had no idea...]][[/note]]. What's dumber than that book? A guardsman that takes it seriously.
*** There is no litanny of stealth, so it is just another way to say: shut up. And shanties are old and usefull.
*** Then again, we're still waiting for a {{Canon}} Guardsman who treats the "Primer" as something other than a glorified toilet roll... (Literature/CiaphasCain makes a reference to troopers reading their primers for inspiration or amusement).
*** Plus, in terms of what's available to most humans the guardsmen's equipment really is very good. A few of the "misinformation" points are also jokes about the setting's StoryAndGameplaySegregation; for instance, the bizarre claim that for all their apparent muscle Orks are no stronger than a human ''actually holds up'' on the tabletop rules[[note]]To be specific, both normal Orks and Space Marines have a strength of 4, while most normal humans have 3, which isn't that far off when the maximum is 10. Humans also have a ballistic skill of 3, Space Marines have 4 and most Orks have 2 (mainly because Orks are too lazy to actually aim, instead prefering to fire wildly into the air as that's more fun)[[/note]].
** Subverted with Ogryns which are are the largest and most physically powerful type of abhuman used by the Imperium. They are so stupid that one got a large chunk blasted out of its chest during a battle and only died when it was pointed out to him later. Apparently this is a common occurrence
** Then you have Orks, who suffer the opposite--Too Dumb To Die. They are so dumb that their ''technology'' is actually the result of their belief in ignorant ideas actually creates a Psyker Field around them, making reality bend to their will. That's right, their "tek" works in part because ClapYourHandsIfYouBelieve.
*** Although the Orks are more than capable of falling straight into this trope when they want to, especially when they are guarding things - the go-to response of Ork sentries is usually "charge at enemy firing weapon", rather than, say "raise alarm". Gunfire and noise are generally unremarkable in an Ork camp, so the Orks are usually rather easy to sneak up on, especially if their enemies are competent. It is also common for Ork armies to fall apart because a campfire brawl escalates into a massive civil war in the space of fifteen minutes, which usually ends with the Orks' enemies [[PassThePopcorn sitting back, watching the fireworks]], then carpet bombing the survivors once the Orks' AA gunners are dead.
*** Since da Orks are essentially giant humanoid fungus who spread spores upon death that eventually become a new Orky ecosystem, their tendency to get themselves killed arguably makes them even more dangerous.
** In the Heralds of Ruin kill-team rules, the Grot Rebels list has upgrades that cause them to take fewer Rout checks because the grots are too dumb to realise they should be taking them - Bad Counting Skills causes them to be more confident because they think they have more troops than they do, and Poor Battlefield Awareness means they pass a rout test for free because they haven't figured out they're losing. These can both lead to more Gretchin dying horribly than would be the case if they simply legged it upon losing half their number like everybody else.
** Also, the Eldar, who despite their ability to predict the future, managed to orgy into existence the fourth god of Chaos (Slaanesh, god of Excess, in case you wondered), which drove their species to the brink of extinction, wiped out their galaxy-spanning empire and dooming their entire race to having their souls eaten upon death.
*** Not so much the Exodites or Craftworlders in that regard, seeing as they were smart enough to leave before things got to that point. The old pleasure cults, however, certainly fit. Before The Fall, many of them were actually ''deliberately'' generating the psychic resonance to create Slaanesh. They believed that a god created from their feelings of pleasure would [[AscendToAHigherPlaneOfExistence allow them to transcend mortal forms and live new, eternal lives dedicated entirely to the pursuit of pleasure]]. [[GoneHorriblyRight They were right]].
** There are a lot of planetary governors who hire the Dark Eldar as mercenaries. In recent lore, a Tau hunter cadre also made the mistake of [[EnemyMine allying]] with them. Big mistake, '''[[FateWorseThanDeath EVEN BIGGER]]''' regret.
** Speaking of the Dark Eldar, they are arguably the biggest idiots in the setting. Their souls are being drained by a Chaos god of hedonism. Their solution? ''To act even more hedonistic'' and hope that their victims' souls will placate She Who Thirsts. And they ''know'' this isn't going to work forever since the Thirst becomes stronger over time.
** There was an incident where a Tau world was under attack by a Tyranid splinter fleet. [[RobotWar Necron]] warships appeared and proceeded to slaughter every living thing before descending to the planet. The overjoyed Tau sent a big delegation including their Ethereal to meet the Necrons, [[RunningGag who proceeded to slaughter every living thing]] before leaving.
*** Funny enough it was a few days into the celebration.
** The Tau are well in the running for worst offenders-and considering they have the entire Imperium to deal with in this competition, that's ''really'' saying something. It doesn't help that they have a ''massive'' case of WrongGenreSavvy, given that Tau are the most idealistic and peaceful guys in the setting ([[AlternateCharacterInterpretation depending on what you think]], though [[CrapsackWorld it isn't saying much]]) and are more likely to ask you "Join or we'll shoot!" than just skipping straight to NoKillLikeOverkill with {{BFG}}s and {{Hand Cannon}}s that leave red mist behind. They happily ally with anyone, have actual diplomats, and generally try to encourage peace rather than shooting. [[WrongGenreSavvy They are unfortunately in the wrong world to try this.]] Say what you will about the Imperium's faults ([[CrapsackWorld ...holy shit we'd be awhile if you did that. Don't, please just don't.]]) but at least they know who not to make deals with.
*** On the other hand, the Imperium [[LawfulStupid takes this too far at times]]. The Tau themselves have made several mutually profitable alliances, so it's obvious that such endeavors aren't always suicide.
** Quite possibly the worst offenders are the Adeptus Mechanicus. So obsessed are they by their pursuit of mechanical artifacts that they will happily enter Necron tombs to study the Necrons (who they consider holy guardians, and their Omnissiah is all-but-stated to be the Necron Void Dragon). Literature/CiaphasCain, '''HERO OF THE IMPERIUM''' has had to literally force Adeptus Mechanicus personnel not to touch Necron tombs at gunpoint, while telling Mechanicus tech-priests how horrible the Necrons are, and yet somehow, that didn't work. In the extremely likely event that a ReasonableAuthorityFigure and OnlySaneMan isn't around to threaten tech-priests not to wake up the Necrons, the tech-priests then have maybe a nanosecond of being surprised before being desintegrated. The Necrons now awake the rest of the tomb and start purging the galaxy of life. [[NiceJobBreakingItHero Thanks, guys.]] [[EpicFail This is not the first time this has happened.]]
** In a setting where ruthlessness is a virtue and mercy to an enemy is often the height of stupidity, the Old Ones may prove to be the biggest bunch of morons around. They had defeated the entire species of both the Necrontyr and the C'tann and could have ended them permanently. However instead of doing the smart thing in 40k, such as dumping them body and soul into the Warp, nuking their planets out of existence, or enslaving them with their godlike mind powers, what do the Old Ones do. They leave both enemies alone. This allowed the Necrontyr to eventually contact the C'tann and supercharge them with the sacrifice of their life-force while the Necrontyr have their consciousnesses placed in near-indestructible robotic bodies. Neither of them make the mistake of taking mercy on Old Ones and wipe them out by constant bombardment of supernovas and black holes.
** The Necrontyr and C'tan made their share of mind-numbingly stupid mistakes as well and paid for them in spades.
*** The Necrontyr declared war on an incredibly powerful race of psychic energy beings out of envy and were predictably horribly outmatched. They attempted to gain an edge by giving the local star-eating sentient gasbags feeding off of their sun powerful living metal bodies and computer brains to use them as superweapons. Without an off-switch. The newly christened C'tan promptly used the living metal to turn the Necrontyr race into their robot slaves and feasted on their souls.
*** The C'tan then took up their slaves' IdiotBall. When the war against the Old Ones, the Eldar, and the Krorks (now known as da Orks) started to go badly for them, the C'tan decided to cannibalize each other. The C'tan killed and ate their own kind. During a war. That they were losing.
*** The end result of all of this stupidity is that the Necrontyr, now known as the Necrons, are trapped in undying metal shells, while the weakened C'tan were shattered by the Necrons after they regained their free will.
** Some characters even know how to manipulate the tendency of this. Take the Viskeons. A minor Xeno race that believed ranged weaponry was without honor and cowardly. [[TheChessmaster Eldrad Ulthran]] steered a [[HordeOfAlienLocusts Tyranid]] splinter fleet their way. They were extinct within a night.
* Having your intelligence drop to 0 in certain {{RPG}}s will render you literally Too Dumb to Live and lead to immediate character death. Presumably your character forgets how to breathe. Others just put you in a persistent vegetative state.
* In ''TabletopGame/MagicTheGathering'' ''Fallen Empires'', the entire continent of Sarpadia was lost because the Order of the Ebon Hand and the Elves were idiots.
** The Order of the Ebon Hand created a slave race called the Thrulls that bred at a rapid pace. Then they started creating intelligent Thrulls capable of using magic so they could assist the Order with experiments. Thrulls who were smart enough to think "Hey, being a slave sucks." The Thrulls, led by this new breed, wiped out the Order.
** The Elves bred an aggressive fungoid species called the Thallids as a food source (using the same magic the Order used to create Thrulls). This worked fine for a while, until the Thallids showed signs of rudimentary intelligence. The Elves were reluctant to wipe out their most reliable food source even when they started brandishing weapons. While the Elves argued over whether they should destroy the Thallids, the Thallids overran them.
** The end result is that Sarpadia in the present day is crawling with Thrulls and Thallids.
** Unrelated to the above, Goblins take this role in most worlds. Goblin minelayers, for example, have [[ExplosiveStupidity a fifty-fifty chance of blowing themselves up]].
* ''TabletopGame/{{Paranoia}}'' is actually at its most fun when the entire party is exhibiting this trope. That's why clones come in six-packs, after all. One of the rules the GM is encouraged to operate upon is "once someone declares their character's actions for the next turn, that's what they're doing, no backsies" ... ''unless'' the changed course of action would be funnier ("Shoot, Vody-O-DOE is setting off a solar grenade? Forget diving for cover; I'm gonna strip off my jumpsuit and get a tan").