Also spelled alternately as geis,[[note]]''Geas'' is a Scottish Gaelic word pronounced as "gesh"; its plural is ''geasan''. ''Geis'' is the Irish equivalent (pronounced the same as in Scottish Gaelic) and its plural is ''geasa'' (pronounced "GYA-sa"). In the [[ genitive case]], Gaelic uses ''geis'' and Irish uses ''geas''.[[/note]] a '''''geas''''' (literally "taboo") is a form of magical compulsion or curse that originates in Myth/CelticMythology. Those under a geas are required to follow certain conditions or risk suffering a penalty bestowed by fate. If you have more than one such geas placed upon you, and they come into conflict, you're screwed. One of the most famous cases is that of Cú Chulainn, who was under numerous geasa, including that he must never eat the meat of a dog, nor refuse food offered by a woman. When an old hag offered him dog meat, he was forced to break one geas or the other, which led to his death the next day.

A geas usually takes the form of either a command or a prohibition: "You shall do this," or "You shall not do this," occasionally followed with a "Or this will happen". In practical terms, the geas may be prophetic, bringing about its own fulfillment either through manipulation of cosmic events or by simply instilling into the subject a compulsion which he cannot resist. If the geas can be broken, and is, doing so typically brings about the death of the subject, either directly or by cosmic retribution.

However, having a geas placed upon you wasn't all that bad. As long as you conformed to it, it would actually make you stronger.

Compare: TheFettered and ObstructiveCodeOfConduct (for mundane versions of this), MagicallyBindingContract (which can have similar effects but is more of a deal rather than a spell or curse), RestrainingBolt (where an object produces similar effects).

JustForFun/NotToBeConfusedWith a ''[[Franchise/CodeGeass Geass]]''[[note]]which actually combines a {{Magical Eye|s}} with a CompellingVoice[[/note]]. Or Geese (plural for Goose) for that matter.




* A very interesting case in ''Manga/{{Bleach}}'' is Giriko and his Time Tells No Lies ability. Essentially, it's a contract he invokes on himself or on others, with the spirit of his watch. It can take multiple forms; increased strength, the power to kill by line of sight, and so on. The catch is that no party involved can violate this contract, or they'll be incinerated--the part that makes it a Geas. Wonder what ever happened to [[spoiler:Giriko's eye?]] Sadly, Giriko doesn't see much action.
** In more of a direct mind control example, Zommari the 7th Espada can hit you with a spell from any one of his 50-something eyes, controlling whatever he hits. If he hits your head, he gets your whole body.
* In ''Franchise/CodeGeass'', the name of the powers is inspired by this, and Lelouch's ability is similar - he can give anyone a command that they will be [[CompellingVoice compelled to obey]]. Being under Lelouch's Geass differs from a Geas in that the person doesn't have to remember to follow that rule - they simply enter a trance, and do as they are told. Afterwards, they have no memory of it. There are no consequences for breaking it because breaking it is impossible [[note]] unless another Geass user, or the Geass canceller, does something to stop it [[/note]]. The "Geass" powers in this series are based on the receiver's personality and desires, and can be anything that affects just the mind of the subject (e.g. by altering their memories or perception), which makes the majority of those powers unrelated to this trope, despite the name.
* In ''Manga/HunterXHunter'', it's eventually revealed that Nen can be used this way to provide a power boost, or to become proficient in a Nen style the user isn't normally able to master. For example, Kurapika eventually gains the ability to conjure unbreakable Nen chains, under the condition that if he ever uses them on anyone other than a Phantom Troupe member, it will kill him. He can also imbed nen spikes in people's hearts, which will kill them if they don't follow a command he gives while doing it. [[spoiler: He manages to effectively de-power Chrollo this way, making the nen spike activate if he uses his powers.]]
* In the anime version of ''Manga/MagicKnightRayearth'', [[spoiler: Alcyone]] turns out to be under this. [[spoiler: The condition is that she'll never reveal Debonair's existence or location to anyone on pain of death. Whenever Alcyone was on the verge of talking about Debonair, she experienced sudden pain as result of the geas, [[BrokenBird which really]] [[BrainwashedAndCrazy doesn't imp´rove]] [[TheOphelia her weakened]] [[EmptyShell mental/physical state]]. When she finally forces herself to tell the Magic Knights about Debonair's location (Cephiro's Underside), in the very last episode, [[CessationOfExistence the geas erases Alcyone from existence]], and she disappears [[DyingDeclarationOfLove reaffirming her love for Zagato]].]]

[[folder:Comic Books]]
* Dunstan in ''ComicBook/ADistantSoil'' is a FairFolk, and he says he is under a Geas that he can't tell a mortal soul who he really is while he's on mortal soil. However, it applies only to soil, that is to say, the ground - which means when he's on a cruise ship or a spaceship, he can actually mention this without violating it.

[[folder:Films -- Animation]]
* In ''Anime/HowlsMovingCastle'', the Witch of the Waste puts a spell on Sophie that ages her into an elderly woman; one of the provisions of the curse is that she can't tell anyone about what's happened. When Sophie attempts to do so at one point, her mouth quite literally seals itself shut.
* This also appears in ''Anime/SpiritedAway'', another Miyazaki film. The witch Yubaba uses [[MagicallyBindingContract enchanted contracts]] to keep her workers in eternal servitude, but is herself under a geas: if someone demands a job, she must grant their request. Yubaba complains about it--"I can't believe I took that oath, to give a job to anyone who asks..."--but is still bound to the rules. There's nothing stopping her from attempting to distract the person requesting employment, or even outright threatening them, but so long as they keep asking, they'll be hired.

[[folder:Films -- Live-Action]]
* ''Film/EllaEnchanted'': The title character is under one which compels her to obey not only any order she's given, but also ''suggestions'' such as by vendors to "buy this sandwich" and "try this perfume."
* ''Film/LiarLiar'': The main character is placed under a 24 hour geas that makes it so he Main/CannotTellALie. If he tries to say a lie, it comes out as gibberish. If he tries to write a lie, he will write the truth. He is even unable to ask a question if he knows the answer to the question is a lie.

* The otherworld beings from the ''[[Literature/TheBartimaeusTrilogy Bartimaeus]]'' books are automatically compelled to obey their orders from magicians by something perhaps like an obsessive compulsive disorder.
** Bartimaeus explains that obeying the orders is necessary, since there was one djinni that refused to kill another djinni it loved. The djinni's repeated refusal to obey the order tore apart his essence and caused him to explode, destroying the prince commanding him and the prince's entire palace. Since then, magicians tend to be more careful about which djinni they summon. Also, and perhaps even more importantly, they direct the spirits they do summon to try to directly go after attacking magicians, thus avoiding such messy business. And, for their part, the spirits have learned to be more careful about forming attachments with each other.
** It's also in the djinn's best interest to just do what the magician commands and get it over with, lest the magician cast the [[AndIMustScream Curse of Indefinite Confinement]] or the [[KillItWithFire Curse of the Shriveling Fire]], which is exactly as unpleasant, painful, and deadly as it sounds.
* Ko-Kraham's curse in ''Literature/Birthright2017'' works as a kind of Geas. Sabrina is compelled to follow the commands Ko-Kraham gives her. There's no condition for breaking it--Sabrina is simply unable to break the commands.
* In ''Literature/DragonBones'', Oreg is magically compelled to serve whoever owns a certain ring at the time. (It's given from father to eldest son, and is unremovable until death). He suffers severe pain if he doesn't obey, even if he's genuinely unable to do as he's told. He also suffers when he's away from both his master and the castle he's magically bound to. He's also immortal, unless killed by the owner of the ring. The implications are quite horrible.
* Literature/ShamanOfTheUndead must lead the souls of the dead to the afterlife, or she loses part of her own soul and somebody else dies in the place of the undead ghost. People killed by BlackMagic are excluded from the geas, because they turn into harpies and as such can't enter the Land of the Dead.
* Features into the backstory of Diarmuid in ''LightNovel/FateZero''. He was bound to serve Fionn mac Cumhaill, but also had a curse on him that caused women to fall instantly in love with him, which is worse than it sounds: his lord's fiancee, Grainne, succumbed to it and placed him under a geas to make him run away with her. They eventually got married with Fionn's consent, but when Diarmuid was mortally injured and needed Fionn's HealingHands to save his life, Fionn delayed long enough that Diarmuid died. As a Heroic Spirit summoned into the fourth Grail War, Diarmuid's only wish is to be able to make up for the whole mess by serving his Master faithfully. [[spoiler:History repeats for poor Diarmuid. His master Kayneth's wife Sola falls in love with him and tries to use the Command Seals to make him reciprocate. Then he is betrayed by Kayneth and forced to kill himself. Diarmuid [[DyingCurse dies cursing]] everyone involved.]]
** Kiritsugu Emiya convinces Kayneth to bow out of the Grail War by, as part of the terms of their deal, offering to bind himself with a geas that will prevent him from harming Kayneth or Kayneth's fiancee Sola-Ui on penalty of losing his magecraft. When Kayneth takes the deal, Kiritsugu does indeed geas himself... [[spoiler:but the geas [[ExactWords doesn't say anything]] about letting someone ''else'' harm Kayneth and Sola-Ui, who are promptly gunned down by Kiritsugu's associate.]]
* ''Franchise/{{Halo}}'':
** The novel ''[[Literature/HaloCryptum Cryptum]]'' introduced a technological variant that can be imprinted by Forerunners on other species (the term ''geas'' being the closest word in human vocabulary to describe the condition). The Librarian imprinted one on the ''entire human race'' to make sure her husband was found and awakened at the proper time, the compulsion being that the humans present at his location would unknowingly sing a song that contained the codes needed to give his reviver passage. Some Forerunners believe that ''their'' forerunners, the Precursors, had imposed a geas on Forerunners as well.
** ''Literature/HaloPrimordium'' takes it farther. One character has to deal with rejecting a geas that forces her to go to the dreaded Palace of Pain, which would ensure her and her companions' deaths. Turns out, gei are subject to change via nearby beacons, and the ones on that particular Halo have been hijacked by the less favorable side in the EnemyCivilWar.
** Another aspect of the human geas is that the memories, and eventually entire personalities, of ancient humans are carried by many humans, "germinating and blossoming" as they do/see/hear/etc. something that triggers it. It gets to the point where the "old spirits" can [[GrandTheftMe hijack their host's body to communicate]]. None of this is considered a pleasant experience, to say the least.
* Used in ''Literature/TheLaundryFiles'' by Charles Stross, which is essentially MI6 meets Creator/HPLovecraft. Figures prominently into the second book, ''The Jennifer Morgue'' where the protagonist is put under a reality-warping geas that essentially transforms him into a [[Film/JamesBond James Bond-esque]] hero (Turns out [[spoiler:this is exactly what the BigBad wants, as he plans on dismissing the geas right before the protagonist is about to win, at which point RealityEnsues and he can kill the protagonist easily. Fortunately, it turns out the protagonist was actually playing the role of ''Bond girl'']]).
* Creator/JoWalton's Literature/{{Sulien}} novels feature several geases, courtesy of the Irish FantasyCounterpartCulture.
* In the ''TheWitchesOfEileanan'' series several people are put under Geasa. Most of them are, or given them by, Khan'cobans (Like Inuit elves with ram's horns), though there isn't a spell involved, it's mostly just a task or obligation that is given social significance if one were to break it or accomplish it. It's less a spell and more a binding of honor.
* In the ''[[Literature/CassandraPalmer Cassandra Palmer]]'' series, the Geis is like a love spell, a magical claim that warns off any would-be suitors and compels the the two people to be attracted to each other.
* In ''Literature/DeepSecret'', Rupert defeats one of the villains by laying a geas on him such that if he tries to use magic again he'll die.
* ''Literature/{{Discworld}}'':
** Parodied in ''Discworld/{{Sourcery}}'', where everyone else thinks the guy under the geas is talking about geese, leading to much confusion. [[spoiler:And then it turns out a geas really is a kind of bird.]]
** Parodied again in ''Discworld/AHatFullOfSky'' and ''Discworld/{{Wintersmith}}'', where Rob Anybody is put under a geas by his wife, Jeannie, to protect Tiffany Aching. It becomes a RunningGag that Daft Wullie keeps thinking Rob means an actual goose.
--> Rob: 'Tis a heavy thing, tae be under a geas.\\
Daft Wullie: Well, they're big birds.
** Golems appear to be under a geas which is very similar to the Laws of Robotics. "A golem cannot harm a human" [[spoiler: unless their writings include the addendum: "unless ordered to do so by duly constituted authority."]]
* In Creator/ClarkAshtonSmith's "The Seven Geases", the protagonist is put under of a sequence of, well, seven geases. Which comes off as mind control.
* In the ''Literature/LordDarcy'' story "A Case of Identity", Lord Seiger is by nature a conscienceless psychopath; a very extensive geas has been laid upon him never to hurt anyone save at the direct order of his superior in the King's Service. He shows no signs of resenting this, but he clearly enjoys those moments when he's let off the leash.
* Fairies in ''Literature/ArtemisFowl'' are under a geas set by their first king, Frond, to never enter a human's dwelling without permission. The idea was that fairies were mischievous and would abuse the humans. Over time, the magic has faded a little, but is still binding. [[spoiler:At least until a certain imp warlock tears it down singlehanded for them between the fifth and sixth books, anyway.]]
* In the ''[[Literature/HeraldsOfValdemar Vows & Honor]]'' stories, the sorceress Kethry's magical sword, Need, compels her to aid women in trouble, beginning with an insistent mental tugging that escalates to excruciating pain if Kethry fails to respond promptly. As noble as the intent of the geas is, in practice Kethry and her partner Tarma mostly find it enormously inconvenient given that it makes no distinctions regarding context and has almost no sense of proportion, forcing the pair to stick their noses into everything from cases of basic domestic violence all the way up to demon-worshiping cults-whether their interference is appreciated by the victims or not. It also gives them a reputation as heroes crusading selflessly on behalf of women everywhere, greatly complicating their efforts to actually make a living as freelance mercenaries since people assume they're more interested in just causes than in getting paid.
** Need's geas also prevents its bearer from ever using it to harm a woman-again with no sense of context or proportion. Kethry's granddaughter Kerowyn, who mostly manages to avoid being yanked around by the sword the way her grandmother was, nearly gets killed when she runs up against an enemy priestess in the midst of a battle and Need abruptly paralyzes her in place rather than allow her to defend herself.
* In the ''Literature/InheritanceCycle'', a character who swears an oath in the Ancient Language is incapable of breaking it (though they only have to obey the letter, [[LoopholeAbuse not the spirit]]). What is more, a person can be compelled to swear such an oath by someone who knows their true name. There is an out, however-if who they are changes so much that their True Name in the Ancient Language changes, all oaths they've sworn up to that point are null-and-void.
* The Faerie Queens are known to put these on people in ''Literature/TheDresdenFiles''. Titania in particular put a geas on the Summer Lady, Lily, and Summer Knight, Fix, both friends of Harry's, such that they could not offer information or help to him, despite them ''also'' owing Harry a favor for past deeds. They manage to get around it, either by Harry transferring the favor (they can't help him, but they can help the person with him), or by the Lady and Knight getting creative (while Fix can't ''warn'' Harry about Summer's forces, he can make a show of ''threatening'' Harry, which still lets him know they're on the prowl).
* There's relatively simple oath spell in ''Literature/SecretCity'' - break the oath and your heart will burn instantly. Judging by behaviour or characters using it, it seems like it's LoopholeAbuse-proof, but only in case of oath itself - if you have transplanted heart, you're completely immune to this.
* ''Franchise/HarryPotter'':
** These are called "Unbreakable Vows" in ''Literature/HarryPotterAndTheHalfBloodPrince'', wherein [[TheMole Severus]] [[ReverseMole Snape]] agrees to let Narcissa Malfoy place this spell on him as an act of good faith. It's explained that breaking the vow is fatal, but this never actually happens in the story so details are vague.
** The MagicallyBindingContract that compels Harry to take part in the Tri-Wizard Tournament in ''Literature/HarryPotterAndTheGobletOfFire'' is really more like this than a contract, since he is entered into it without his knowledge or consent. The consequences of breaking the contract are not explored and are a subject of much FridgeLogic.
* In ''ForgottenRealms'':
** During and before the Time of Troubles, Kelemvor and his family were under such a curse. Originally the curse condemned Kelemvor's family to never accept payment for helpful deeds. In Kelemvor's case, the curse flipped so that he can never do anything for anybody without accepting a fair compensation for it.
** In the ''Literature/CounselorsAndKings'' series from the same setting, a wizard-word oath is a self-inflicted, usually minor version - a [[TheMagocracy Halruaan]] wizard who swears to do something "By wind and word" will be bound to follow through, though it's up to the wizard him or herself to interpret the oath. For example, when master wizard Basel Indoulur's apprentice Tzigone offends and humiliates his rival [[SmugSnake Procopio Septus]], Basel swears he will "deal with her accordingly", which Procopio intended to mean "punish her" but Basel interpreted to mean "reward her", since he thought Procopio had it coming to him. [[spoiler: More seriously, supporting antagonist Dhamari Exchelsor is bound by such an oath to never summon any creature he doesn't understand and can't control. Since his plans require him to summon FairFolk who more than fit those criteria, he needs to manipulate Tzigone into helping him]].
* In ''[[Literature/ZeusIsDead Zeus Is Dead: A Monstrously Inconvenient Adventure]]'', any oath sworn by the River Styx (figuratively or literally) is binding, even for a god. Hermes even wiretaps the Styx so he can spy on anyone who utters such an oath in secret or in unthinking rage, and uses this to [[spoiler: blackmail Zeus]].
* The title character of ''Literature/EllaEnchanted'' is given, at birth, the "[[BlessedWithSuck gift]]" of obedience, and she has to do whatever she is told, provided the order is given in a language she understands. (And she's an InstantExpert at languages.)
* In ''[[Literature/CircleOfMagic The Will of the Empress]]'', Shan implies in a very {{squick}}y way that "There are ways to make mage wives obey you."
* One of the ''{{Literature/Xanth}}'' books is titled ''Geis of the Gargoyle''.
* ''Literature/SchooledInMagic'': There are many spells of this sort mentioned or shown. People are compelled to be loyal, obedient and tell the truth with them, etc.
* ''{{Literature/Neverwhere}}'': This seems to be what maintains the truce at the Floating Market. It ''can'' be broken, but after what happened to the last person who did, several centuries before the novel's timeframe, even the worst villains don't dare.
* Played with in ''Literature/TerraIgnota''. Chagatai believes J.E.D.D. Mason, who believes himself to be a god, placed a geas on her, which led her to put herself under a ''[[CoolAndUnusualPunishment modo mundo]]''. After she accidentally destroyed a priceless book, J.E.D.D. Mason told her that the protagonist of every work of fiction is Humanity, and the antagonist is God. Ever since that Chagatai's found herself unable to enjoy any entertainment without agonizing over that struggle, swearing off fiction forever. It's pretty clear that nothing would happen should she revise that decision, but Chagatai herself strongly believes that something unusual happened.
* ''Literature/TheThrawnTrilogy'': {{Deuteragonist}} Mara Jade is a former Emperor's Hand, a Force-sensitive operative answering directly to Emperor Palpatine. During Darth Vader's HeelFaceTurn at the end of ''Film/ReturnOfTheJedi'', Palpatine reached out to her with the Force and planted a compulsion on her: "''YOU WILL KILL LUKE SKYWALKER.''" This becomes a serious problem for her during the trilogy, which sees her more often than not ''collaborating'' with Luke. [[spoiler:LoopholeAbuse in the form of Mara killing Luke's ''clone'' at the climax of the third book resolves the geas.]]

[[folder: Live Action TV]]
* ''{{Series/Misfits}}'': A young Roma woman puts a curse on Alex after he refuses to help her retrieve something that had fallen in the water. It makes him help everyone who asks, or he'll have to feel like he's drowning. Finn quickly exploits this by making Alex lend him money. She takes it off after he shows contrition.

[[folder:Myths & Religion]]
* This is all over the place in Myth/IrishMythology:
** Diarmuid O'Duibhne was "under geis" not to hunt the Boar of Ben Bulben. But Fionn [=McCumhaill=] tricked him into participating in a hunt that tracked the very same boar, and the boar killed Diarmuid.
** Cú Chulainn was under geasa never to refuse an offer of food, and never to eat dog meat. Of course, eventually his enemies [[MortonsFork offered him dog meat]]. He ate, and was killed soon afterwards.
** Cú Chulainn's son, Connla, was placed under a three geasa: to never turn back on a journey, to never turn down a challenge and to never give his name. This leads to Connla seeking out his father when he came of age, [[spoiler: only to die at his father's hands when refused to speak his name]]. Depending on the version, the one who put the geis on him was either his mother who did not leave Cú Chulainn on the kindest terms or else Cú Chulainn himself.
** High King Conaire Mór was under a whole host of geasa. Eventually events conspired to make him break all his geasa in a single day. The same night, he was killed by sea-raiders.
** ''Literature/TheChildrenOfTuireann'': Lugh of the Long Hand is under geis never to refuse a second request. The sons of Tuireann exploit this when he sends them off on a quest to redeem themselves for killing his father. First, they asking Lugh to lend them the horse of Manannan, which he refuses, then ask him for the boat of Manannan, which is what they actually want.
* Samson in the Literature/BookOfJudges of the [[Literature/TheBible Old Testament]] was bound to the terms of the [[ Nazirite vow]] (he was not allowed to partake of wine or anything else made from grapes, touch a dead body, nor cut his hair) due to a promise made by his mother; breaking the vow would result in the loss of the super strength God had blessed him with. Sure enough, when Delilah, who had been hired by the Philistines to trick him into revealing his secret weakness, shaved him bald, he was left defenseless and promptly taken captive. [[spoiler:It turned out the effect was as temporary as his baldness.]] By that point Samson had already broken the other terms of the Nazirite vow. The hair-cutting was just the last straw.

[[folder:Tabletop Games]]
* As befits the genre, the 3rd Edition ''TabletopGame/{{GURPS}}'' sourcebook Celtic Myth has rules for imposing geasa on characters.
* There is a spell called geas in ''TabletopGame/DungeonsAndDragons'' that forces the character to fulfill the terms. Clerics call the same spell "Quest", and also have a "Mark of Justice" that places a curse on a character who breaks the conditions of the Mark.
** The powers of Wu Jen and characters under the various Vows of the Book of Exalted Deeds have specific behaviors or tasks they must perform to maintain their powers.
* Geasa were used in 3rd edition ''TabletopGame/{{Shadowrun}}'' to recover points of magic that had been lost by shaman/magicians/adepts. Your character had to accept some sort of condition to recover a point of magic. Usually anything the GM wanted/was willing to allow but classic ones were some sort of talisman that you had to keep on your person, having to fast on a regular basis, spend time in meditation, or only use magic in certain circumstances. Breaking the geas reduced your magic back to it's normal level.
* In ''TabletopGame/MageTheAwakening'', geasa can be inflicted by mages who have gained Mastery of the Fate Arcanum. Working against the terms of a geas (or even failing to actively do something required by the geas) inflicts a very debilitating curse. A geas (and the curse for breaking it) can be made hereditary, affecting the subject's descendants as well.
* ''TabletopGame/SeventhSea'' has the geas, a special ability that can be purchased at character creation. As long as you have the geas, it gives you an extra experience point each session, but if you fail it's condition you lose the geas forever.
* This is the power the demonic lilim have in ''TabletopGame/InNomine''. They can look into a person's eyes and discover their true desires (ranging in intensity from 'needs a light for their cigarette' to 'needs to get a million dollars'). If they then fulfill one of them (or more) for the person, they can (attempt to) attach a geas to the person to do something in return. They're limited only by the scale of the desire (an easy-to-fulfill desire would grant a geas that only lasts an hour or so) and the target's ability to resist the compulsion. The dangerous part is the target is usually ''not aware'' the lilim is doing this, and doesn't have to agree to a DealWithTheDevil for the lilim to get the geas. The only real defense is a combination of never looking a lilim in the eyes, and never accepting anything they offer, ever.
* In ''TabletopGame/{{Exalted}}'', [[AbusivePrecursors the Primordials]] placed one on their creations, [[ServantRace the gods]]. It forbade them from directly attacking any Primordial (except in self defence or on the order of [[KingOfAllCosmos Theion]]). The gods got around this by giving power to mortals whose free will means that their actions are seen as sperate from the gods. They were then free to help these humans as long as they themselves didn't attack a Primordial; anything else was fair game.
* In ''TabletopGame/KitsuneOfFoxesAndFools'' "geased" is a consequence that prevents a fox from regaining foxfire for two turns.

[[folder:Video Games]]
* Lancer in ''VisualNovel/FateStayNight'', whose true identity is Cuchulainn himself, has a geas that if a man from Ulster uses Caladbolg against him, he must lose the fight, [[spoiler:but it never happens]]. The sequel, ''VisualNovel/FateHollowAtaraxia'' has Shirou play a trick on him involving his original two geas, though they are never stated outright: Three female friends of his from school offer Lancer a hot dog, an offer he can't refuse and (were it actually dog meat) something that could potentially kill him. This is actually related to how he originally died.
** At one point in Unlimited Blade Works Rin threatens to use Geas on Shirou. One [[MultipleEndings bad ending]] in Heaven's Feel occurs when she [[ChekhovsGun follows through on her threat]], placing Shirou under a Geas and using it to stop him from [[spoiler:saving Sakura]].
** In ''LightNovel/FateZero'', Kiritsugu uses one to eliminate Lord El-Melloi as a Master: he kidnaps El-Melloi's fiancée Sola-Ui and threatens to kill her, unless El-Melloi orders his Servant Lancer [[note]](who's actually Diarmuid of the Love Spot, NOT Cuchulainn)[[/note]] to commit suicide, removing himself from the Holy Grail War, in which case Kiritsugu will geas himself into never harming El-Melloi or Sola-Ui. El-Melloi accepts (as a magus himself, he can see that the self-geas scroll Kiritsugu is holding is genuine), and then... [[spoiler:Kiritsugu's partner Maiya immediately kills both El-Melloi and Sola-Ui... after all, ''Maiya'' [[ExactWords wasn't under a geas to do them no harm]].]]
* In ''VideoGame/NeverwinterNights: Hordes of the Underdark'', as a way of avoiding the ButThouMust faux-choice, the player character gets a geas to kill the evil sorceress Valsharess.
* [[spoiler:Yoshimo]] in ''VideoGame/BaldursGateII'' is under a geas to betray you at a certain point of the plot.
* Referenced in ''VideoGame/WildARMs3'' - Janus, [[spoiler:after acquiring his demon form]] is bound to follow the Prophets' instructions, under pain of being blown apart by the remote bomb called ''Geas''.
* In ''VideoGame/QuestForGloryIV'', the Hero is placed under a geas by [[spoiler: Katrina]], giving him three days to recover the rituals needed to free the [[SealedEvilInACan the Dark One]]. The geas is removed once he returns successfully with them.
%%* The entire plot of FinalFantasyXIII.
* Continuing from the ''Franchise/{{Halo}}'' plot thread mentioned in the "Literature" section, ''VideoGame/{{Halo 4}}'' has [[spoiler:the Librarian imprint mentioning to the Chief that a good part of the UNSC's advancement, including Cortana's design and the Chief himself, has to do with the geas she implanted into humanity over 100,000 years ago]].
* In ''Videogame/DragonAgeInquisition'', an Inquisitor with Arcane Knowledge can figure out that Abelas' warning that the Well of Sorrows' power comes with a price isn't hollow: anyone who drinks from it is put under a powerful geas. Morrigan is dismissive of the geas since she believes that Mythal is long gone. [[spoiler:Then it's revealed that Mythal is ''Flemeth''.]]
* In ''VideoGame/FireEmblemFates'', the [[spoiler: Curse of Valla]] can be seen as a geas. [[spoiler: After Anankos took over, he places a spell under the land: if anyone who's been there and returned to the other lands tries to talk about it outside of Valla's territories, his/her body will [[DisappearsIntoLight dissolve into water]].]] As a result, in the past [[spoiler: Azura's mother Arete, the former Queen of Valla and later the Queen of Nohr, pretty much [[HeroicSacrifice killed herself to tell a young Azura about Valla itself]] so she would keep the knowledge about it, and Azura could ''not'' properly tell the Avatar about Valla until the GoldenPath took place.]]
* In ''VideoGame/TalesOfBerseria'', a geas is placed on [[spoiler:Bienfu]], forcing him to [[spoiler:act as TheMole to Velvet's party and leak their actions to the Abbey]]. It's a powerful enough geas that even ''Magilou'' can't detect it until [[spoiler:she catches him talking to a sylphjay as they sail towards Titania]].

[[folder:Web Comics]]
* In ''Webcomic/TheOrderOfTheStick'', Belkar is put under a Mark of Justice which prevents him from dealing lethal damage (a D&D rules term, basically meaning any damage that isn't the kind you'd use in a sport fight -- and Belkar never bothers with sublethal damage when he can get away with lethal) to any living thing within the bounds of a settlement. He also cannot travel more than a mile from Roy, on pain of suffering from a sickening curse. The curse is eventually [[spoiler:invoked when Belkar stabs the Oracle, [[CrazyPrepared who had established a village around his tower for exactly that purpose]], and then removed by a cleric who needed Belkar to protect him from an invading horde of goons]].
* One of the powers that Acanthus Mages such as Amical or Tyler have in ''Webcomic/{{Morphe}}''.

[[folder:Web Original]]
* In ''Roleplay/TheGamersAlliance'', the archdemon [[FourStarBadass Malphas]] ends up under a geas when he kisses fellow archdemon [[TheVamp Nina Heeate's]] enchanted ring, and the geas forces him to serve Nina's every whim. It turns out that Nina was using magic and her female physique to mess with Malphas's mind, which confused Malphas enough to make the geas take effect. Nina doesn't keep Malphas on a tight leash, however, and instead lets him do what he wishes as long as he doesn't stand in her [[TheLegionsOfHell horde's]] way. The geas also requires Malphas to keep his mouth shut about the whole endeavour, further ensuring that Nina's part in the whole mess stays out of the limelight.

[[folder:Western Animation]]
* An unusual example in ''WesternAnimation/{{Gargoyles}}''; Demona once placed Goliath under a spell compelling him to obey the spoken orders of "whoever held the spell." Brooklyn seized the book from her, found the page with the compulsion spell, and tore it out before Demona could reclaim it, so that Goliath would follow Brooklyn's orders rather than Demona's. After Brooklyn and Goliath defeated Demona, Eliza found a way around the spell: holding the page, she commanded Goliath to act as he would if he were ''not'' under a spell from then onward. So essentially, for the rest of the show's run, Goliath was under a geas--to be himself.
* In ''WesternAnimation/{{Freakazoid}}'', [[TheScottishTrope a character who must not be named]] has the power to kidnap children, but only [[SpeakOfTheDevil if they say his name out loud]]. At one point in his debut episode, he's in a bunk at a camp filled with kids, but is only able to speak to and interact with the ones who are foolish enough to say [[JustForFun/CandleJack Candle Ja-]]
* Pearl of ''WesternAnimation/StevenUniverse'', in several episodes, can be observed slapping her hands over her own mouth when certain subjects come up in conversation. It's revealed late in Season 5 that this is under command of her original owner, [[spoiler:Pink Diamond, to never again speak of how the two of them faked Pink Diamond's shattering at the hands of "Rose Quartz", who for that instance was Pearl in disguise, but otherwise was actually ''Pink Diamond herself.'']]