->'''Alister:''' But you can't fuse a Trap Card with a Monster!\\
'''Kaiba:''' Looks to me like I just did, Alister.
-->-- ''Anime/YuGiOh - Ep 150, [=4Kids=] version''

Games have rules. Those rules are around to [[CompetitiveBalance make everything fair and give everyone a reasonable chance for success]]. [[MagicAIsMagicA They do not always make logical]] ''[[MagicAIsMagicA sense]]'', [[MagicAIsMagicA but they're there.]]

However, sometimes the story isn't paying attention. This trope is where the rules of a game within a given work are made so vague or complex that there is no possible way they can be understood. Sometimes, the story just makes things up as it goes along. Hopefully, the improvisation will make sense.

This is not about the differences between rules in a work and rules in a game it's based on (the former will often be inherited from the latter), but when the rules of a work don't make sense and violate their own [[InternalConsistency internal logic]].

Deliberate and clear cheating which acknowledges that the characters are bending the rules, or finding some technicality to exploit, are also not this trope. The key is implausibility and being unbelievably complex.

If it involves liberties with the rules of real sports/games it's GretzkyHasTheBall. If there really aren't any rules (or the rules change very frequently), then it's {{Calvinball}}. If a ''new'' rule is specifically crafted to prevent an existing abuse, it's an ObviousRulePatch.

Also compare HowUnscientific, NewPowersAsThePlotDemands, GameplayAndStorySegregation, ScrewTheRulesIMakeThem, and AintNoRule. GoldenSnitch is a subtrope. Be sure to stop by SeriousBusiness on your way out.



[[folder:Yu-Gi-Oh! examples]]


[[folder: Pre-Battle City examples ]]

* It is important to note that many of the examples in this section are based off of earlier parts of the series, where card interactions were much more complex and simulated a lot more cause and effect. This was because the series used a lot of games that had these kind of interactions, and the rules hadn't been set in stone yet.
* In the first season, Duel Monsters was played on a large field with multiple areas of attack. Different monsters had different field advantages depending on where they were played that it was never possible to keep track of with the limited information given. Often the bonus would vary wildly from doubling a monster's stats to tripling them to raising them by 50%. Duelist Kingdom standardized it to 30%, resulting in weird things like [=PaniK=]'s Castle of Dark Illusions having 250'''9''' defense points.
* In the fifteenth episode of the second series anime, Yugi uses a monster called Catapult Turtle to launch a Fusion Monster, Gaia the Dragon Champion, at another monster, [=PaniK=]'s Castle of Dark Illusions. This destroys the Dragon Champion on impact, causing Yugi to lose most of his Life Points (going from 1606 to 300 for no apparent reason) and the castle's flotation-ring to fall off, but it seemingly doesn't destroy the castle... until Yugi mentions that the Castle is now being held up by Yugi's Swords of Revealing Light. Yugi ends his turn, ending the effect of [=SoRL=], thus causing the destruction of the Castle... and all of [=PaniK=]'s monsters, which were underneath and, due to [=PaniK=]'s Chaos Shield, couldn't get out of the way in time. If these had been real, physical creatures engaged in a battle, this would be reasonably creative and entirely valid. But they're just cards in a card game, [[MagicAIsMagicA subject to the rules thereof]], so Yugi's trick had ''absolutely no basis in the rules'' ([[RuleOfCool but it looked cool]]).
* In the same episode as the above, the flying castle itself has the effect of hiding the villain's monsters in darkness, so Yugi can only attack the darkness and get his monsters killed by cards he can't see. How exactly is that supposed to work ''without'' holographic technology? 'You're attacking my monster. Sorry, it has higher attack points than yours. No, I can't prove it, that would defeat the whole purpose of the shrouding darkness. Just take my word for it, will you?'
* In his duel with Kajiki/[[DubNameChange Mako]], Yugi calls an attack on "Full Moon". Three major problems with that. First, "Full Moon" is Yugi's own card and is on his side of the battlefield. Second, it's a magic card, not a monster. Third, he's trying to ''stab the moon with a sword''. Yet not only does this somehow work, it dramatically alters the battlefield, causing the ACTUAL tide (which actually rose when Yugi first played Full Moon, how a card can control an actual real-life tide is never explained) to go out [[FridgeLogic lower than it was before he summoned the moon]], and ''beaching Kajiki's sea monsters''. Konami is well aware of how ridiculous that is, as evidenced by this card: [[http://yugioh.wikia.com/wiki/Attack_the_Moon! Attack the Moon!]]
* The Yugi vs. Kaiba duel in the Duelist Kingdom arc gives us this little gem: Yugi is able to fuse one of his monsters, Mammoth Graveyard, with Kaiba's Blue-Eyes Ultimate Dragon using Polymerization to fuse the Living Arrow card (which has since become [[http://yugioh.wikia.com/wiki/Spell_Shattering_Arrow Spell Shattering Arrow]]) with Mammoth Graveyard and then fire it at Kaiba's monster, resulting in a different Fusion... or something... in any event, the result was on Kaiba's side of the field. Because it was a Fusion of an "undead" monster and a "living" monster the unnamed Fusion Monster's ATK and DEF decreased by the ATK and DEF of Mammoth Graveyard.
** Later, Yugi attacks it once its ATK was low enough for his weaker monsters to defeat it. However, it is stated that because Blue-Eyes Ultimate Dragon is a Fusion Monster that requires three Fusion Material Monsters, it must be attacked three times to completely destroy it, so Yugi's attack killed only one head. No other Fusion Monsters do ever display this characteristic and this is never played up again.
* In Yugi's duel with the fake Kaiba, it's revealed that Mystical Elf, a Normal Monster at first glance, actually had the effect of transferring its ATK (1100 at the time, due to a Magic Card) to another monster you control. It also could, apparently, stop Spell Effects because it was "chanting a mystical chant."
* ''Makiu, the Magical Mist'' gets this an awful lot. It does something different every time it's played -- in the duel with Insector Haga, it washed away the spores of the Great Moth and powers up Summoned Skull; in the duel with Jonouchi, it's used during Jonouchi's turn to stop Thousand Dragon's attack; finally, in the duel with the possessed Keith, it weakens all his Machine-type monsters. To make things even better, in the original manga, the card was ''printed'' with the effect: "Water vapor surrounds all monsters on the field". Apparently, the players' imaginations were supposed to take care of the rest. This was a callback to the original design of the Yu-Gi-Oh card game, being an RPG similar to Dungeons and Dragons with a randomized card system. However, due to the ambiguity of the card effects, the idea was scrapped. These examples are a prime reason.
* Battle Ox, a monster without an effect, was resistent against FIRE monsters, just so Jonouchi would get a disadvantage against Kaiba. Additionally, Dinosaur-type monsters were weak against FIRE monsters for no reason, giving Jonouchi an advantage over Dinosaur Ryuzaki. This is later dropped.
* Summoned Skull also gets an effect in the duel with the Rare Hunter, where it charges up Alpha the Magnet Warrior's attack by 200 points. Throughout the series, Summoned Skull is implied to attack with [[LightningCanDoAnything electricity, which is used to give him a huge variety of added abilities]] (additional ATK points, greater range, etc). Furthermore, the first time Yugi uses Summoned Skull (when dueling Pegasus [[TheTapeKnewYouWouldSayThat through the video tape]]), Summoned Skull attacks physically, which is why it can't attack Pegasus quickly enough to win Yugi the duel. Of course, it could easily have attacked quickly enough with electricity.
* Flying monsters could not be attacked by ground monsters. This is {{Retconned}} later, since all monsters are able to levitate anyway.
* Pegasus combines this with ScrewTheRulesIMakeThem when he introduces Toon Monsters, cards that nodody has seen before and are only exclusively used by him. Since he is the creator of ''Duel Monsters'', he is able to use cards that defy rules, but they still are technically legal, so it's actually an aversion.
* This trope is justified when more than two duelists participate in a duel. There are no written rules on how to organize such duels, so basically as long as your opponent agrees to your terms any system is fair game.
* Bandit Keith's Machine-Type monsters were immune to magic attacks to give him an advantage over Jonouchi, even though Yugi's Dark Magician was able to destroy the Meikyu Brother's Labyrinth Tank in an earlier episode.


[[folder: Post-Battle City examples ]]

* The Battle City rules themselves count as this. The rules used in the show were deliberately moved closer to that of the real life TCG with no greater justification than "Kaiba changed the rules for his tournament" even though he in no way owns Duel Monsters. [[ScrewTheRulesIHaveMoney Then again...]]
* Each time The Winged Dragon of Ra is played it has a new power. First, there is that special writing which can only be seen under the light of the God (and that means the hologram). When Mai summons it, it doesn't work, since you need to read the text (that is written in Egyptian) to activate it. Marik promptly reads the text, taking Ra to his side of the field and activating it. Next battle, it has two new abilities: it can increase/decrease its attack points by decreasing/increasing his owner Life Points at the owner's will, and it can attack at the same turn as it has been summoned. And against Jonouchi, Ra has an Phoenix Mode that allows Marik to destroy all monsters of the opponent at the cost of 1000 LP, and it cannot be harmed in this mode. And this is all before the battle is against Yugi, when it shows its real power.
* In the duel between Yugi and Marik, the latter uses all his Life Points but one to add to The Winged Dragon of Ra's attack points. Because Marik has made this duel a Shadow Game, this manifests itself as all of Marik's body except one eye becoming part of Ra. Because of this, Marik is able to later use the card De-Fusion to separate himself from Ra and restore his life points. One problem with this: Marik isn't a monster, or even a card. Unless Kaiba's holograms are good enough to hide his entire body and make it appear somewhere else, Marik only appeared to be 'fused' to Ra because of the Shadow Game, so 'de-fusing' shouldn't have been possible within the Duel Monsters game (as they were never actually fused in the first place).
* Averted in Kaiba's reaction to the Winged Dragon of Ra. Midway through the series, Kaiba discovers through his computer that Ra has several 'unwritten' powers. Seeing as it's his tournament and he made the rules for it anyway, he could just declare that only the abilities listed in the text count, making Ra much easier to defeat, but he doesn't. Kaiba justifies this by saying doing so would really defeat the point of the tournament in the first place, which is to see who deserves to be called the best; if Kaiba were to [[ScrewTheRulesIMakeThem nerf his opponent's best card just so that he can win]], Kaiba would lose face, and more importantly, [[{{Hypocrite}} sell out his own principles]].
* Obelisk's Soul Max effect changed during the Battle City tournament. First, it could destroy all enemy monsters and inflicts 4000 damage, but later in the finale, Obelisk's ATK increases to infinity instead. Not only that, Obelisk changes its color when powering up, something that didn't happen with the previous Soul Max effect.
* Bakura tends to do this more often than not as his entire strategy. In Battle City, Dark Necrofear works to summon a Field card called Dark Sanctuary, which seems to be activated by the system reading his mind to see what card he designated the target without anyone else knowing. How this could actually be enforced under any situation, period, is not entirely clear though it is worth noting that this is not the case in the Japanese version. And in his final appearance, he manages to be in three places simultaneously and completely flouting the rules in all three. As Zorc, he ignores the effects of four separate all-destroying attacks. As Honda-Bakura, he uses a strategy that works purely by making his graveyard go away. The cards aren't banished and don't go to his deck or hand, which is the only place they can go, but the graveyard just... goes away. And as the game master, [[ScrewTheRulesIMakeThem he explicitly said he's making up the rules as he feels like it]].
** A somewhat odd example from the Dark Sanctuary duel: Yugi notes that Bakura's strategy will fail because he needs to play more than five Spell/Trap cards at once to achieve it. Bakura then says that Dark Sanctuary allows him to have more than five on the field at once. Yugi then counters that it doesn't matter what the card ''says'' - there is simply no mechanism in Kaiba's duel disk for Bakura to play a sixth card [[note]](in the Japanese version, he says that Dark Sanctuary lats him use his Monster Card Zones)[[/note]]. This is glossed over, as Bakura never gets to five anyway.
* The Doma arc gives us the Legendary Dragon cards. The Legendary Dragon cards are neither monsters (they're usually played in the Spell and Trap Card Zone), Spell Cards (they can be played even when a monster effect prevents Spell Cards from being played) or Trap Cards (they don't have to be Set before being used), they are just "something".
* During his Duel with Kajiki, Jonouchi's Alligator Sword is inside the Fairy Box, but when Umi is played, the monster almost drowns. Aside from the FridgeLogic that alligators cannot be drowned that easily, Umi has no effect that would harm monster cards that cannot breathe underwater, a mechanic that only works with the hologram system, or negate effects of other cards, such as Fairy Box.
* When Kaiba introduces the new rules with the Duel Disk System, Fusion Monsters couldn't attack in the same turn when they are summoned. This rule disappeared since the fourth season.
* During the life threatening duel between Yugi and Jonouchi, where the winner gets the key to free himself from the anchor, Yugi chooses himself as Jonouchi's Spell Card's target. Yugi lose all of his Life Points, but Jonouchi realizes that his Spell Card allows him to be attacked by Yugi's Red-Eyes Black Dragon, so Jonouchi would lose all of his Life Points as well. Regardless how you look, Yugi lost his Life Points first, and Jonouchi needs minutes to figure out that he himself can be attacked. Both effects of his Spell Card does not work simultaneously.
* Before the duel between Jonouchi and Rishid, people could apparently create Fusion Monsters as long they have Polymerization. When Jonouchi drew it and he has three monsters on the field, the Spell Card was useless because he cannot fuse them for some reason. Presumably, having the fitting Fusion Monster is indeed needed, even this was never an issue before.
* In Tea's duel against Crump, Tea activates a Spell card that summons a Dark Magician to the field. But she didn't have Dark Magician in her deck, so she just magically steals it from Yugi's deck, who was merely watching at the time.
* Another aversion, a similar case like the Toon Monsters above, Yugi first believed that Noah is violating the rules when he introduces Spirit Monsters. Noah explains that the Spirit Monsters are legal cards that are secretly created by Pegasus, but since nobody has ever heard of them, they are a completely new type of Monster Cards in this game.
* Noah's duel with Kaiba/Yugi. Kaiba loses due to a card effect without running out of life points, at which point Noah turns him to stone. At which point, everyone seems to forget that Kaiba had ''lost'', and acts as if he is simply unable to play on, so Yugi takes over from where Kaiba was the previous turn, and on top of that is for some reason allowed to mix his own deck with Kaiba's remaining cards for the rest of the match.
* In ''Manga/YuGiOhR'' there was an odd rule pertaining to Fusion Monsters; a duelist's field was considered to contain both the Fusion Monster and its components. This meant Yugi's Arcana Knight Joker counted as ''four'' monsters when determining the ATK of Devil's Eraser, which had 1,000 ATK times the number of opposing monsters. (The rule implemented simply to make it strong enough to defeat Arcana Knight Joker.)
* ''Anime/YuGiOhTheMoviePyramidOfLight'' is infamous for its errors, with some of them involving ignoring rules or effects.
** In the simulated duel, Kaiba summons Blue-Eyes Ultimate Dragon. The writers forgot that Slifer's Lightning Blast effect would decrease Blue-Eyes' ATK by 2000. Also, Obelisk's Soul Max effect happened during Kaiba's turn, which would be impossible.
** Jonouchi being attacked on the opponent's first turn. Not to mention that the attacking monster wasn't played face-up in vertical position.
** While in the English dub, Anubis tenfolds Theinen the Great Sphinx's ATK with [[ScrewTheRulesIHaveSupernaturalPowers magical powers]], in the Japanese dub, Anubis activate Theinen's (anime) effect. Theinen gains the ATK of all monsters that are in Anubis graveyard, a total amount of 31,500 ATK.[[note]]3x Blue-Eyes White Dragon (3x3000), Blue-Eyes Ultimate Dragon (4500), Blue-Eyes Shining Dragon (3000), Familiar Knight (1200), Rare Metal Dragon (2400), Des Feral Imp (1600), Paladin of White Dragon (1900), Peten the Dark Clown (500, two of the three are banished), Spear Dragon (1900), Andro Sphinx (3000) and Sphinx Teleia (2500).[[/note]]
** When Anubis replaces Kaiba in the duel against Yugi, the rest of the duel is 1/3 this trope and 2/3 ScrewTheRulesIHaveSupernaturalPowers. First, Obnoxious Celtic Guardian is destroyed in battle by Sphinx Teleia which has 2500 ATK, despite the fact that Obnoxious Celtic Guardian cannot be destroyed by monsters with 1900 or more ATK (which saved him from Noah once), and Teleia's effect doesn't activate, which would defeat Atem. Second, Anubis sets Theinen the Great Sphinx like a Spell or Trap Card on the field, despite it is a Monster Card (no, he doesn't set it in Defense Position). And finally, Yugi manages to destroy Theinen the Great Sphinx with his three Egyptian Gods without using an effect and he wins the duel. It cannot be either Obelisk's Soul Max effect, since it's Anubis turn, or Ra's Phoenix Mode, since Yugi cannot pay 1000 Life Points with only having 50. Yugi just combined the power of his three Egyptian Gods without activating one of their effects. For the rule breaking part, see the main page of ScrewTheRulesIHaveSupernaturalPowers.
*** This situation is partially {{retcon}}ned by Konami's later creation of [[http://yugioh.wikia.com/wiki/The_Creator_God_of_Light,_Horakhty The Creator God of Light, Horakhty]], a sort of ultimate God Card that is can be brought out by tributing the original three Egyptian Gods and automatically winning the duel. This still fails to explain how Yugi's win occurs on Anubis's turn, however.
* The Five-Headed Dragon was a Ritual Monster in the Virtual World arc, mostly because the Big Five didn't have Dragon-type monsters that can be fused into it. Later, at the beginning of the Grand Championship arc, it is a Fusion Monster, and it remains a Fusion Monster as seen several times in ''GX''.
* In the anime, the Egyptian God Cards cannot be effected by any card effect apart from each other's, and in Ra's case, not even that. However, in the first duel with The Seal Of Orichalos, it does raise Obelisk's Attack Points. Apparently, because the Orichalcos is more ancient, it has more power than the Egyptian Gods.
* The duel against Dartz has quite a bit of this. First, it is said that The Seal Of Orichalos can't be made to leave the field by any means. However, Dartz does remove it, in order to activate an enhanced version, which is later replaced by an even more enhanced version. Then when the Pharaoh summons the Legendary Knights, they destroy the Orichalos anyway. When one of Dartz monsters is destroyed, he pays all of his Life Points to summon Divine Serpent, a monster with infinite Attack Points, and an effect that makes him able to continue, even though he has no Life Points. Unsurprisingly, despite being hit by an attack with infinite power behind it, [[PlotArmour the Pharaoh still doesn't lose]], and uses a card that also makes unable to lose, as long as he keeps his Dark Magician Girl in play. Then the Pharaoh has two of his Legendary Knights attack Divine Serpent, and make their attacks constantly reflect each other, until their Attack Points raise to infinity. Then he suddenly sacrifices them in the middle of an attack, so as to summon a fused form of the Legendary Knights, which gains the infinite Attack Points, and then is able to destroy Divine Serpent, and win the duel.


[[folder: Second and later series examples ]]

* ''Anime/YuGiOhGX'':
** The effect of Magical Cylinder seems to depend on the era it is played. In the ''Duel Monsters'' era, it reflects the attack to the attacking monster. In the ''GX'' era, it reflects the attack directly to the opponent. The latter is played early on by Sho, while the former is used by Yugi during his duel with Judai, who somehow traveled to the past.
** Call of the Haunted's effect was changed to its real life counterpart, while in ''Duel Monsters'', it had an entirely different effect -- not to mention it was a Spell Card (in the original) back then.
*** The same happens to Deck Destruction Virus and Jinzo.
* ''Anime/YuGiOh5Ds'':
** The new introduced Synchro Monsters with new rules related to them. This is justified, considering that the game has advanced so far between ''5D's'' and ''GX'', it is actually an aversion. This feat is later repeated with the Xyz Monsters in ''ZEXAL''.
** Yusei is dueling Rudger. Rudger has his Earthbound Immortal Uru on the field, as well as the Field Magic Card "Spider Web". Earthbound Immortals cannot be attacked while a field magic card is on the field, so Yusei pulls some LoopholeAbuse and declares that he'll instead attack Rudger directly, a strategy that, needless to say, is impossible...[[SubvertedTrope now]]. This was actually the original ruling for the specific wording of this particular attack-immunity effect possessed by the actual Earthbound Immortal cards (originally used for the Legendary Fisherman of Kajiki (the freaky fish guy) fame). The original ruling had been [[ScrewTheRulesIMakeThem overridden specifically by Konami]] for these and subsequent cards to make them more viable. Cards that retained the old ruling now specify, via errata, that they allow for direct attacks so as to avoid confusion.
** And later we have Yusei, Jack and Rua creating new cards in the middle of a duel, including two different monsters from the same blank card at different points!
** In the Dark Signer arc, two of the Duels of Darkness were interrupted at the right moment when Yusei and Aki are about to lose. Later, Rudger and then Demack tell Yusei that Duels of Darkness cannot be cancelled, despite Kiryu and Misty exactly did that. While in Kiryu's case it makes a bit sense, since Yusei's D-Wheel broke in the duel which would automatically end the duel, but Misty's excuse was not very convincing.
** Riding Duels are duels on motorcycles. They have some special rules and special Spell Cards, the Speed Spells. However, Yusei, Jack and Crow team up together to duel Rex Goodwin. The twist? They duel on their motorcycles, but Rex Goodwin [[IHaveTheHighGround has just high ground]] and stands there the whole time. There is no mentioned rule of semi-Riding Duels being possible. Like his three opponents, Goodwin is limited to use Speed Spells and he gets Speed Counters, which can increase or decrease the speed of the D-Wheel, but he has no D-Wheel. Later, he even says that Crow and Jack don't get any turns as long as they cannot drive their D-Wheels after they crashed ([[ScrewTheRulesIHaveSupernaturalPowers and they crashed because he sabotaged them in the middle of duel]]), but he still isn't riding a D-Wheel, yet he is excluded from the rule.
** The effects of some cards were changed to make them closer to their real life counterparts. For example, Junk Warrior's effect was a Continuous Effect in the early part of the anime, later it's changed to a Trigger Effect. And Blackwing -- Sirocco the Dawn could be Special Summoned from the hand if there are only monsters on the opponent's side; the Special Summon part is later changed to "Normal Summon without Tribute".
* ''Anime/YuGiOhZEXAL'':
** The ''Duel Monsters'' game has become closer to the real TCG, so Normal Summoning monsters in face-up Defense Position is now an illegal move, something that was totally fine in previous series.
** In Episode 43, Kaito Releases Yuma's monsters to summon his Photon Kaiser. This is iffy enough because the rules don't seem to specify whether the two are sharing fields or not (the previous episode implies this is not the case, as Kaito's Photon Pressure World Field Spell damages everyone who doesn't control a Photon monster, and Yuma is damaged by it). What happens next is a blatant example, however. To clarify, Photon Pressure World's effect is that when a Photon monster is summoned, everyone who doesn't control a Photon monster takes damage equal to the summoned monster's Level x 100. Kaito summons Photon Kaiser, and for some reason (most likely that Yuma would lose otherwise), Photon Pressure World doesn't activate. With no good reason. And the card text is written in such a way that the effect is compulsory. At best it might be argued that Kaito summoned Photon Kaiser to Yuma's field (which it plainly wasn't, and in any case has no basis to begin with). Doing so would damage III and IV, but not Kaito because he had Galaxy-Eyes Photon Dragon out.
* ''Anime/YuGiOhArcV'':
** Yuya literally creates an entire new kind of summoning and type of monster cards, Pendulum Summoning and Pendulum Monsters, literally in the first episode, likely due to currently-unknown magical powers. However, everyone watching reacts as the audience does, with confusion and interest, at the very least. Many people think that's an AssPull, and even Yuya needs 291 more duels to figure out how to Pendulum Summon again. Since the various Special Summonings play a major part for the setting and the plot, this trope is played straighter than anything above.
*** Since Yuya doesn't fully understand the Pendulum mechanic himself, it feels like this when a part of the mechanic occurs that he himself didn't know.
** Also, due to the rule change in real life, in this anime, the player who starts the duel cannot draw in the Draw Phase.
** During Sora's duel with [[SpellMyNameWithAnS Yuto/Ute]], Yuya joins them ''in the middle of the duel'', playing on Sora's side. This obviously violates the rules without any question, but his Duel Disk accepts his action as legit and activates the Battle Royal Mode. Yuya has his own field and starts with 4,000 LP while the other two duelists don't, giving him an advantage and Yuto a big disadvantage. Additionally, the plot progresses a lot thanks to Yuya joining the duel and major questions of the series are revealed as a result.
*** Sora also disappears in the middle of the duel, so it becomes back to 1-on-1. This is still a weird situation for a duel. Again though, Sora didn't withdraw so much as he was forcibly teleported [[spoiler: back to his own dimension]], so the magical/sci-fi element isn't exactly something we have rules for in real life. Yuri's duel with Yuzu is also ended without a winner or a surrender when the same thing happens to him.
** The Battle Royal is not only legal in-universe, but it is also used in the Maiami Championship. The only illegal part is that you cannot join in the duel when you aren't participating in another on-going duel. If you do, you get 2000 penalty damage. This might be a special rule for the tournament, because people won't get much advantage like Yuya did before. Generally, the Battle Royal Mode is a plot devise that allows the writers to break more rules and traditions from previous series in order to advance the plot or to give their characters more CharacterDevelopment. Or just for RuleOfCool.
*** The 2000 Life Points intrusion penalty is also inconsistently applied across the board. Overwhelmingly it's the protagonists who get hit by it while the bad guys don't even in situations where they should. It gets to the point where it starts affecting one specific character only ''after'' he undergoes a HeelFaceTurn, confirming beyond a shadow of a doubt that it only exists to put the good guys at a disadvantage. And then later, the enemies are also affected by this, just so they would lose easily.

[[folder:Other Anime/Manga]]
* ''Anime/{{Bakugan}}'' has a serious problem where it's not even clear what the rules ''are'' to begin with beyond "whoever's mon loses is the loser". How and when you could use the cards and the exact rules of team fights were even more ill-defined.
* ''Anime/BattleBDaman'':
** The show seems to forget every so often that ''shooting'' your opponent's fingers... or head... or friends... with a ''marble capable of shattering stone'' is, in most games, a [[UnnecessaryRoughness flagrant foul]]. Not that the real things shoot like that, but still...
** To say nothing of all the weird table setups, bizarre tournament events such as a marble-powered elevator, and other head-breakingly improbable challenges.
** Especially notable is that, according to one of the final battles, joining a game already in progress and ganging up on a single person is allowed by the rules. Because ganging up equals the power of friendship. This is despite the villains being condemned for it earlier in the show.
* In ''Manga/MiyukiChanInWonderland'', Humpty Dumpty forced Miyuki to play a giant game of chess against her own [[EvilCounterpart lesbian reflection]] with full-sized scantily-clad human women as chess pieces, and whenever one piece took another, she'd bitch-slap the shit out of the piece that's just been taken, and [[TheNudifier her clothes would disappear]]. Also, the stakes are that whichever Miyuki lost would have to take her clothes off. And THEN it starts getting weird. the real Miyuki never said "Check" or "Checkmate", and we didn't see a single red/black piece take a single white/blue piece, and yet, all of a sudden, Humpty Dumpty declared the Reflection the loser and the reflection stripped.
* Anime/MegamanNTWarrior usually only changes the amount of damage that certain attacks do to even the playing field (Megaman's default megabuster is a lot more powerful), and since the characters are actually using chips in an environment with proper physics, it makes sense that certain things can be done. But at the same time, at one point in the series, they decided to speed up the combat by making chips more like equipment rather than one-time attacks. Adding this rule would probably destroy the internet when the guys with meteor chips start using them...
** Probably the most noticable example would be the Life Sword Program Advance. At first it appeared to be a wave of some sort. During the final battle of the tournament Megaman and Protoman were dueling with them like actual swords.
** In "The [=NetMobile=] Grand Prix" the main cast enters a friendly virtual race. While the chips they use in the beginning made some sense (Nitro chips and change of accessories) the chips gets increasingly random near the end, with at least one racer turning his car into a ''fighter jet''.
* Anime/{{Pokemon}}:
** During Satoshi/Ash's match with Hiroshi/Richie in the Indigo League, the sleep status was counted as a KO, a rule that was never used before and never again afterwards. It served as another DiabolusExMachina for Satoshi to lose the Indigo League.
** Ground-Type Pokemon were more than once hurt by Electric-Type attacks, but in the Johto tournament, with zero {{Foreshadowing}}, the Ground-Type was revealed as immune to electricity, and after this, they switch between immune and not immune as the plot demands.
** The Ghost-Type is generally portrayed as strong to Psychic-Type... outside of one episode of the Johto arc, when he is portrayed as weak instead.
** Solarbeam is a ChargeAttack, but sometimes certain Pokémon just fire it immediately without charging and with no Sunny Day to accelerate the process. This is especially blatant in the Kalos Saga.

[[folder:Collectible Card Game]]
* CCG magazine ''[=InQuest=] Gamer'' (then just ''[=InQuest=]'') proposed a variation of ''MagicTheGathering'' they dubbed "KangarooCourt", which allowed players to apply real-world logic to the game, effectively acting out this trope long before ''Anime/YuGiOh'' existed. One given example showed a player arguing that using [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=190574 Pacifism]] on [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=159321 Angry Mob]] should destroy the mob, since it's no longer angry and would disperse.
* ''TabletopGame/MagicTheGathering'' sometimes has this happen during the design phase of a set. Notably, during one test, [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=230768 Reaper from the Abyss]] was about to murder itself due to its Morbid ability, so the designer playing it added "non-Demon" to the playtest card.
-->'''Opponent''': You can't do that!\\
'''Designer''': I redesigned it while the ability was on the stack.
* ''TabletopGame/MagicTheGathering'' has also had a situation similar to Pegasus using cards no one had ever seen because he created the game. Richard Garfield has used custom cards several times, including an adorable case when he proposed to his girlfriend. It took several games, because he never drew his Proposal in the first two.

* In ''Film/TheHungerGames'', the rules are changed midgame to allow two winners, if they are from the same district. When Katniss and Peeta are the last two standing, a voice over rescinds that rule, meaning one of them would have to kill the other. [[spoiler: Rather than bow to the wishes of the evil government, they decide to eat poisonous berries and deny them ''any'' winner. Government relents and names them both victors.]]
* The Creator/SylvesterStallone film ''Film/OverTheTop'' builds up to a [[ItMakesSenseInContext double-elimination arm-wrestling tournament]], and the announcer reminds us of this just about every time he speaks. Stallone's character, Lincoln Hawk, loses once to John Grizzly ([[CrazyAwesome whose psyche-out techniques include DRINKING MOTOR OIL and EATING CIGARS)]] in the quarterfinals, and his spirits are broken before his son reminds him that it's a double-elimination tournament and [[IronicEcho repeats a speech from earlier in the film]]. Hawk comes back to beat both Grizzly and [[TheRival Bob "Bull" Hurley]] to win the championship...but wait! We never did see Grizzly or Hurley lose before that, did we? Most of the championship went by in the form of a montage of every single match, in which we saw Hawk, Grizzly, and Hurley easily winning all of their matches...then we saw Hawk lose to Grizzly...and then we saw Hawk beat Grizzly, Hurley beat the other quarterfinalist, and Hawk beat Hurley after a single (albeit extremely long and climactic) match. The entire "double-elimination" aspect was apparently thrown out as soon as Hawk was done using it for a plot device.
* In ''Film/TheCannonballRun'', they make a point at beginning of each team punching a card in a time clock to note their start time and the cars left at staggered intervals. This indicates that the winner would be the team with the best overall time, not necessarily who makes it to the finish first. At the end, all the racers act like it's the first team to punch their ticket that wins and JJ is mad a Victor for stopping to save a dog, despite the fact they left quite a bit after the "winner". Everyone else just gives up.

[[folder:Live-Action TV]]
* An episode of the live-action kids drama ''Series/{{Zoey 101}}'' had a ''Series/BattleBots''-style remote-controlled robot war, where the main characters lose to the [[HollywoodNerd stereotypical nerds]] after their bot destroys the other with a hammer. When the main character's best friend comes in with her own tiny bot, the nerds laugh at it until it fires a huge ''laser'' at the other bot, completely destroying it and winning the match. Apparently, there [[LoopholeAbuse Ain't No Rule]] saying you can't use military lasers in the competition.
** Whereas the hammer being slightly too tall when upright [[SelectiveEnforcement got said nerds disqualified.]]
** ''Series/MalcolmInTheMiddle'' once did something similar, where Hal designed a robot with a weapon that fired bees at the other humans. It's never stated if this would have been allowed in, but the other characters are more concerned with how wrong it sounds than what the rulebook would say.
* ''Series/StargateSG1'' does this for the eponymous Stargate. The Stargate is a machine that can create a wormhole and take you across the galaxy in the blink of an eye. At the beginning of the series, they set out a few simple rules for the Stargate technology: The wormhole can only terminate at another Stargate (justified, in that it's basically a souped-up telephone), the wormhole only transmits in one direction (because of reasons, and science, and stuff), the wormhole can only remain active for 38 minutes (because of other reasons, and different science, and stuff), nothing can come through the wormhole if there's something directly in front of the Stargate's event horizon (this one actually makes sense!). After they lay out these rules, they proceed to break them in every succeeding episode and explaining it away by having a scientist say something polysyllabic. The 38 minute deadline is violated repeatedly, but for some reason this always surprises people.
* ''Series/StarTrekVoyager'' played with this in the episode "Worst Case Scenario". B'Elanna Torres found an old unfinished role-playing holodeck program Tuvok made that dealt with a potential Maquis uprising on Voyager. It was made in all seriousness, but they try to finish it up as a decent role-playing game instead. However, when they try to edit the program, they find that Seska (crewmember turned traitor) reprogrammed it as a no-win situation with EverythingTryingToKillYou. To buy time for the engineers to shut down the holodeck, Janeway took control of the game stats and became a DeusExMachina working ''for'' Paris and Tuvok. The game would send crew members to kill them, and Janeway would materialize phasers in their hands. Eventually ended with the computer going for the RocksFallEveryoneDies solution, but Tuvok figured a clever way out of that.
* Rudy in ''Series/KickinIt'' seems to be under the pressures of both a franchise owner and a corporate employee with the rights and privileges of neither: he's said to own the dojo and its' mentioned that he borrowed money from relatives to invest in it, but Bobby Wasabi can close the location and lay him off at will.

* Dragon Poker, a game popular in the world of Robert Asprin's ''Literature/MythAdventures'' consists ''entirely'' of this. In-universe, its described as the most complicated game in the world, and has so many rules that to anyone who's never played (I.E. the readers) its functionally indistinguishable from CalvinBall. Gameplay is only vaguely poker-shaped and is equal parts moves that have never been mentioned before using cards that have never been mentioned before, and [[RulesLawyer Rules Lawyering]] over obscure rules and modifiers based on absurd things like the phase of the moon or which cardinal direction the player is facing when sitting at the table which completely change the values of cards and the outcomes of moves. Pretty much ever single move, card, or rule of the game gets mentioned exactly once in the entire series, and almost none of them are ever explained to the reader. This is, of course [[RuleOfFunny quite intentional]].
* The climactic duel in ''[[TheHeirChronicles The Warrior Heir]]'' is traditionally fought to the death, but [[spoiler:Jack and Ellen tell the organizers to go stuff it in the end, gambling on the fact that there aren't a lot of Warriors and the traditionalist Wizards aren't about to reduce their numbers]].
* In the second/third Rangers Apprentice book, [[spoiler: Hal is banished from Araluen, but only for 1 year]] Lampshaded by the advisors around them.

* In ''Pinball/SharkeysShootout'', the game rules change according to which opponent the player is currently up against, as well as whether the current game is 8-ball or 9-ball.
* Creator/SternPinball's ''Pinball/{{Transformers}}'' table changes the game rules according to what faction the player chooses at the beginning, such as whether certain shots will increase the Score Multiplier or the Bonus Multiplier, or how jackpots are collected in the multiball modes for the factions' leaders.
* In Creator/{{Stern}}'s ''Pinball/{{ACDC}}'' and ''[[Pinball/KissStern KISS]],'' the game rules change according to what song the player has currently selected.
* ''Pinball/GameOfThrones'' imposes different rules depending on which House you choose initially. Also, the houses you've allied with will give different benefits when you reach the "Hand of the King" mini-WizardMode.
* ''Pinball/DoctorWho'' has the player choose one of the seven Doctors of the classic series; each of which confers specific benefits for one part of the playfield. Transmitting a Doctor will permanently apply that Doctor's benefits for the rest of the game; locking a ball will let the player choose another Doctor.

[[folder:Pro Wrestling]]
* Wrestling does have rules. Or, rather, different matches have rules. Wrestling does not always stick to these rules, or they may simply make up new ones whenever a confusing situation arises. A match breaking its own rules is usually the hallmark of a botch that had to be covered up, or the bookers just not caring. Some examples of this include:
** Royal Rumble matches. Especially in early years, whether or not someone could eliminate themselves or whether they had to be propelled by someone else was totally inconsistent. A rule about not being able to eliminate yourself was made up on the spot to cover for Macho Man botching. Also, the Royal Rumble twice ended in a draw. Once, they were both declared winners. Once, the remaining two fought it out until there was only one winner. Again, this was to cover a botch.
** WCW was quite notorious for a while for totally ignoring the rules of their matches, like brawling outside in a cage match, or scoring a win by pinfall in a match type that couldn't be won by pinfall.
** Ironman rules, especially what happens in a tie, are always changing to create drama and generally conspire to get the heel closer to victory.
* A notorious one is the "30 Day Rule", where a reigning champion must defend the title at least every 30 days. At this point, WWE has pretty much abandoned it, but it tended to only be enforced when RealLifeWritesThePlot or it made sense within a storyline to force a heel champion to defend or sometimes for a face with a kayfabe injury.

[[folder:Tabletop Games]]
* Most tabletop roleplaying games incorporate what's generally known as "Rule 0," which is [[ScrewTheRulesIMakeThem the GM's word is law]], giving him free rein to adjust or ignore the rulebook at his whim as well as simply make up new rules on the spot. It's to be hoped that the GM will only do this to make the game more fun. HouseRules should generally be negotiated and agreed upon before play begins.
* When players have rule disputes in wargames, best solution is usually to simply roll a die, then check the FAQ for a ruling sometime later. Players often like adding story-based rules to the games, too.

[[folder:Video Games]]
* An actual gameplay point of ''VideoGame/FinalFantasyTacticsAdvance''. The game has "Laws", which are basically rules, the judge draw "law cards" and if ANYONE break the rules, get sent to jail [[TheAIIsACheatingBastard (Except bosses)]]. As the game goes on, more laws appear and you have to obey multiple laws at the same time, some of those laws are just stupid (No damage to monsters? How is that fair?!) and only appear because the plot requires the game to get harder. That sounds fairly simple until you see the "Advanced Laws", only Judgemaster Cid can use them and they are obvious plot devices.
** When Judgemaster Cid is trying to arrest Ezel, he uses an advanced law that "prevents him from using any ability", this is rather confusing since, for starters, it's an individual law (which is cheating by itself) and laws never PREVENTED you from doing anything (just punishment after breaking).
** The second time is even weirder when you fight [[CopyCatSue Llednar]], who is actually invincible.[[spoiler: Cid says Llednar's Omega spell is too dangerous to use, and throws an advanced law at him to prevent him from using it. Except it doesn't prevent anything, after a short time Llednar will start to cast the spell, but Cid sends him to jail before he finishes it. Technically speaking, Llednar never managed to break the law since he was sent to jail before that, but thanks to that you can win the battle.]]
** [[spoiler: And lastly, there is an advanced law called "Fortune" created by the last boss and given to Llednar that makes him completely invincible. This goes against everything you learned so far, being immortal isn't a breakable rule and only Judgemaster should be able to use advanced laws. The last boss just says ScrewTheRulesIMakeThem]]
* In ''VideoGame/NoMoreHeroes2DesperateStruggle'', Sylvia decides to start changing the rules to the UAA matches, such as setting up a Battle Royale, allowing Charlie and his 24 cheerleaders to fight as a team, allowing Shinobu to fight for Travis but giving Travis the ranking, and [[spoiler:killing assassins who lose the ranking match without dying by their opponent's hand]].
* The gravity in ''VideoGame/SuperMarioGalaxy'' can't seem to make up its mind on how it works. Sometimes it pulls things towards the center of the nearest planetoid, and sometimes it's a universal field that points in a general "down" direction. The [[VideoGame/SuperMarioGalaxy2 sequel]] is even more inconsistent, to the point that the player is required to blindly leap off some ledges with no clue as to whether Mario will safely [[BabyPlanet land on their underside]] or [[FloatingPlatforms plummet towards infinity]].
* ''VideoGame/FinalFantasyX'''s Spira is to death [[NarniaTime what Narnia was to time travel]]. Things start simple enough: when someone dies, their spirit must be "sent" (that is, [[{{Psychopomp}} magically transported]]) to the Farplane, Spira's version of the afterlife, and those not sent eventually transform into monstrous, feral creatures called fiends. Things get complicated later with the "Unsent," [[UnfinishedBusiness strong-willed]] (read: plot important) people who die but aren't sent, effectively tangible ghosts, and can pass on either by willingly fading away or by being defeated and then sent. (Whether an Unsent can actually be around a sending without suffering any "ill" effects is also inconsistently portrayed.) Still later, we see zombie-like Bevelle soldiers wandering the ruins of Zanarkand, humans in appearance but fiends in mind and spirit. [[spoiler: Seymour]] is just the opposite: he dies multiple times, becoming an unsent after the first time, achieving progressively more powerful fiend-like powers each time he returns but never losing his human identity, in contrast to [[spoiler:Auron]] who is also an Unsent but never receives any fiend powers. Then there's the Fayth, people who willingly gave themselves up to animate Aeons, who can be tied to one person's Aeon or everyone's. Plus, there's [[spoiler: Tidus and Dream Zanarkand, memories of people who ''may'' have existed maintained by the Fayth]]. Finally, there's [[spoiler: Yu Yevon]], who is more of a WalkingSpoiler than the rest here.
* The penultimate level in ''VideoGame/FearEffect'' reveals that when Wee Ming comes into contact with blood, anyone in the surrounding area mutates into a monster, and yet Lam somehow doesn't mutate in the brothel like all the prostitutes even though he was standing ''right next to Wee Ming.'' Similarly, when [[spoiler:Lam]] mutates at the very end, Glas is unaffected by Wee Ming's BloodMagic even though ''he'' is standing nearby.
* In ''Videogame/{{Fallout 3}}'', killing an evil character usually yields no negative karma and may even give the player positive karma. Not so in the Tenpenny Tower quest, a storyline about a feud between a demented Ghoul named Roy Philips and the Ghoul-hating human residents of Tenpenny Tower. Here, killing the ObviouslyEvil Roy Philips gives the player negative karma as a not-so-subtle way to encourage the player to try diplomacy instead. [[TheRevolutionWillNotBeCivilized Good luck with that.]]
* ''Franchise/AceAttorney'' introduces new laws relatively frequently, almost without exception to inconvenience the defense. The most egregious example of this happens during [[spoiler:the second half of case 6-5, the prosecutor of which being the monarch of the country the trial is being held, who has no problems literally rewriting the law on the spot. Of course, she's also the culprit of both crimes you're going to court for, so she has a vested interest in winning the trial at all cost]]. In fact, the only way to win that case is to [[spoiler:make sure that these new rules are unenforceable by turning the royal guard against the prosecution]].

[[folder:Web Comics]]
* In the FAQ for ''Webcomic/TheOrderOfTheStick'', Rich Burlew states that he doesn't have the exact ''TabletopGame/DungeonsAndDragons'' stats for the characters so as not to limit what he can do with the story. He's also displayed a willingness to stretch the D&D rules to fit the plot. By way of example, [[http://www.giantitp.com/comics/oots0373.html Miko Miyazaki's escape]] from a ''forcecage'' spell prompted readers on the forum to point out that that's not how ''forcecage'' works.
** Of course, in that particular example, [[spoiler: it wasn't exactly ''forcecage''; it was ''Xykon's Moderately Escapable Forcecage'', since Xykon [[BatmanGambit planned for Miko to escape anyway]].]] However, it's entirely possible that this was a hasty {{retcon}} by Rich Burlew in response to the abovementioned forum posters.
** The forums spent many a thread statting out [[http://www.giantitp.com/comics/oots0639.html Familicide]]. On the one hand, it could genuinely be done by epic spellcasting rules. On the other hand, initial estimates measured its Spellcraft DC by the hundreds, which may have been technically possible (it was researched by an epic level wizard, and cast by a wizard with the power of ''three'' epic level casters) but was insanely unfeasible and unlikely. [[ZigZaggedTrope On the third hand]], if you're willing to [[GameBreaker seriously cheese the rules]] (and your GM lets you get away with it), there ''is'' a notorious bug in epic spellcasting which allows one to build arbitrarily powerful spells for a small fixed cost. In any case, it's unlikely Rich bothered to come up with actual stats for the spell.
** And inevitably [[LampshadeHanging lampshaded]] when Durkon employs [[http://www.giantitp.com/comics/oots0352.html Control Weather]] to generate thunder as a [[MakeMeWannaShout sonic attack]]. The following strip opens with an angel questioning the use of the spell thus, and Thor basically telling him to mind his own beeswax and not contradict the thunder god.
** [[http://www.giantitp.com/comics/oots0453.html A later comic had one of the Southern Gods telling (well, snarling at) Thor to back the hell off when he tries a similar feat outside his designated territory]].
** The backstory justifies this by showcasing the gods coming to an agreement not to directly intervene in each other's realms, after the last time divine arguments resulted in their last planet being destroyed.
* ''Webcomic/{{Goblins}}'' author Thunt ostensibly based his comic on Third Edition ''TabletopGame/DungeonsAndDragons'', and yet frequently writes low-level characters dealing improbably-strong blows to high-level characters, like [[http://www.goblinscomic.com/03032010/ here]] and [[http://www.goblinscomic.com/06222009/ here]]. In both cases, the wooden guy with the green hair is level 10, fighting against level 2 characters. He's claimed that the fights 'work out fairly' within the HouseRules he uses, at one point averting the trope by giving a play-by-play explaining how the fight would play out if it were at a gaming table.
** It would be irresponsible, however, to not point out that one of the second level characters in question is named [[MinMaxing Minmax]].
* In ''Webcomic/{{Erfworld}}'', the DM set up an unwinnable scenario, flat-out saying that the only the players could have won was to cheat. After the DM ends up stuck in the scenario, he does that: he [[spoiler: uses necromancy to reanimate a ''[[FantasticNuke volcano]]'']].

[[folder:Web Original]]
* In the first RP of ''Roleplay/DarwinsSoldiers'', scientist player characters weren't allowed to carry heavy weaponry. For some time in the first RP, Zachary got to wield a bazooka and he wielded a RPG in the final battle.
** The rule about "no heavy weaponry for scientists" was rescinded for the second and third [=RPs=]
* One of the guiding principles of the ''Roleplay/GlobalGuardiansPBEMUniverse'' was that the needs of the story story overrode the rules whenever necessary.
* Mercilessly parodied in ''WebVideo/YuGiOhTheAbridgedSeries'' by exaggerating the trope as it was played in the source material UpToEleven. In fact, it's strongly implied ''nobody'' has ever played the game properly: the rules are apparently so overly complicated and impossible to understand, Duelists don't even bother reading them and just make up what they can do on the spot as their duels go on. When Kaiba announces the Battle City Tournament will actually follow the game's official rules, this is considered as a big twist by the other characters.
--->'''Joey''': The best part is, I have no idea how I did any of this!
--->'''May''': Do you even ''read'' the descriptions on your cards?
--->'''Joey''': Wait, there are ''words'' on those things?!
** Kaiba actually once tried to learn the actual rules (something treated both by Mokuba and himself as a DangerousForbiddenTechnique) in order to prepare for the tournament, and programmed the IA he was dueling to play entirely by them. Upon checking these rules, the IA promptly decided they were way too needlessly complicated and wiped them out from its memory, before proceeding to play as everyone does.
--->'''Kaiba''': Even the most advanced computer in the world can't figure out this game!

[[folder:Western Animation]]
* In ''WesternAnimation/TheFairlyOddparents'', the fairy bible "Da Rules" provides frequent examples of this trope. One being that new sub-points of certain rules are added so that the plot can't be magically fixed. For example, magic can't interfere with love (i.e. wishing a partner to move away to [[MurderTheHypotenuse eliminate a rival]]). In a later episode, they add that the rule doesn't mean both parties have to be [[StalkerWithACrush in love with each other]]. It has also been hinted that new rules to avoid some wishes appear every time a wish goes horribly wrong.
** Parodied in the episode where Poof debuted, in which a rule was meant to be implemented but nobody got around to it. It's a joke that's used at least twice when Timmy asks why he can't wish one of his Godparents to be pregnant, with Wanda then Jorgen Von Strangle (the main rule maker himself) having to check Da Rules when asked about it, and leading to the above.
** Also of note is that [[GenieInABottle genies]] aren't bound by Da Rules, but this [[JackassGenie isn't necessarily a good thing]].
** One episode has Cosmo picking Da Rules and ripping off the page that says he they can't help Timmy win the movie's competition, but he never does it again. The funniest part is, Timmy changed his mind later so he didn't even break the rule.
* ''WesternAnimation/{{Futurama}}''[='=]s blernsball is an example of this trope. This is done for RuleOfFunny, of course.
* ''WesternAnimation/TotalDramaIsland'' fits this, mostly because of Chris, aka Mr. ScrewTheRulesIMakeThem. It can go from "not a rule to be had" to "dem's the rules" in about two minutes. [[LampshadeHanging Lampshaded]], of course, by [[VillainousBreakdown Heather]]. Lawsuits factor in as well.

[[folder:Real Life]]
* Carnies have a term called an ''alibi'', which is when someone who has apparently won a game of chance is told about a previously undisclosed rule, in order to be able to deny giving them a prize. A common example is stating that the player crossed an invisible "foul line." At least most of them are up front about not allowing underhand shots.
* The [=NFL=] has some rules that are so obscure that even coaches are not generally aware of them. Sometimes they are called attention to in playoff games, which leads to accusations that the league is manipulating the outcome to allow the more popular team to advance to the SuperBowl. Infamous examples include the [[http://en.wikipedia.org/wiki/Tuck_rule tuck rule]], which changed the outcome of the [[http://en.wikipedia.org/wiki/Tuck_rule_game 2002 [=AFC=] Divisional Playoff Game]], and the "[[http://en.wikipedia.org/wiki/Bert_Emanuel Bert Emanuel]]" rule, so named when the Tampa Bay Buccaneers had an apparent pass reception overturned by officials in the [[http://en.wikipedia.org/wiki/19992000_NFL_playoffs#NFC_Championship:_St._Louis_Rams_11.2C_Tampa_Bay_Buccaneers_6 2000 [=NFC=] Divisional Championship Game]]. The latter ensured that the "Greatest Show on Turf" offense of the St. Louis Rams, considered to be more ratings-friendly than the Buccaneers' stifling defense, would reach the championship; while the former extended the chances of the New England Patriots and Tom Brady's star power. A non-playoff example occurred during a 2010 game between the Detroit Lions and Chicago Bears, in which a potentially game-winning touchdown catch was overturned when officials ruled that Lions receiver Calvin Johnson failed to maintain control of the ball because [[http://www.huffingtonpost.com/2010/09/12/calvin-johnson-touchdown-_n_713897.html he set it down too quickly after catching it]].
** The problem with the NFL the amount of nit picky rules that the human refs are supposed to take into account along with the general vagueness of a lot of rules coupled with the limitations of the review system. For many years, the official NFL rule book was not available on the internet ([[http://www.nfl.com/rulebook now it is]], along with the offical casebook), and most people aren't privy to NFL officials meetings that clarify interpretations of the rules. Most of the examples would definitely be subjective for these reasons (they may appear to be bad calls to people on the losing end or 50% of non-vested viewers while the other half will feel otherwise). An example: during a punt the ball was rolling into the end-zone and a player from the punting team dove onto the ball, initiated contact with the ball outside of the end-zone and released contact with the ball after it was in the end-zone. It was ruled a touchback, it was challenged, reviewed and upheld. The rule that allows you to down the ball is called illegal-touching and doesn't clarify (at least in the internet rules version) whether you just have to touch the ball or have to possess the ball for it to be downed. It's interesting because for it to be considered a fumble or a muffed reception, the receiving team merely needs to graze the ball. Interpretations of the rules seem to follow along the US Justice system whereby previous interpretations continue until corrected by a higher authority.
** Illegal touching means that the ball is downed when the kicking team gains control of it and cannot be downed in such a way as to give the receiving team worse field position than when the kicking team first touched the ball. Thus, if a member of the kicking team attempts to down the ball, but it goes into the endzone off his hands, it's a touchback. If the ball is deflected toward the receiving team's endzone and then downed, the ball is placed back where it was first touched. And now for the GameBreaker: if a ball is touched by a member of the kicking team and a member of the receiving team then gains control before the kicking team does, the ball can be advanced by the receiving team, and the receiving team CANNOT FUMBLE. If the kicking team recovers a fumble or intercepts a lateral pass on such a play, the ball is downed instead of going back to the kicking team. This means that, except for the risk of throwing the ball back through your own endzone for a safety, there is no risk to attempting a rugby-style multi-lateral pass play (which like pulling the goalie in ice hockey, is normally reserved for an end-game desperation play, but is a free option on a delayed penalty, wherein the opposing team is not allowed to gain possession).
** Especially frustrating is the league's apparent knee-jerk reaction to any hit/tackle that causes a major injury to a few players by declaring it illegal, leading to players getting massive fines/suspensions for hits that many observers claim was "just a good football play" and those observers complaining that the game is becoming sissified.
* UsefulNotes/{{NASCAR}} has been known to change the rulebook on the fly as needed. Sometimes it seems arbitrary, sometimes it's in response to apparent overdominance, and sometimes it's just figuring out that having people race at full speed to the start/finish line when a caution comes out is less than safe when the reason for the caution flag is a guy sitting helpless a few hundred metres in front of said start/finish line, as such an incident happened with Dale Jarrett in Loudon in 2003.
* Similarly, the [[UsefulNotes/FormulaOne Formula 1]] rules on pit stops, tyre management and Safety Car scenarios (just to name the most usual ones) seem to change every year, if not every few months.
* [[SocietyMarchesOn As society is constantly changing]], the law needs to be constantly revised, resulting in constant new laws introduced, and changes to original laws. Due to the obvious potential for abuse, many countries have a law banning or restricting ''ex post facto'' laws (also known as a Grandfather Clause), which makes laws unable to be applied retroactively (in other words, you can't prosecute someone if whatever they did was legal at the time).
* The code for buildings, electricians, plumbers, etc is ''constantly'' being revised and changed to meet with new technology or to address things that were later realized to be not restrictive enough or ''too'' restrictive. Keeping up with these code changes is a major part of these peoples jobs. Like above, there is also a Grandfather Clause which states an installation that was up to code upon installation is ''still'' up to code even if such a thing would be prohibited nowadays, unless of course it is so blatantly dangerous that it is an active hazard (knob and tube wiring, lead piping for potable water, and friable asbestos being three major examples of things that ''must'' be removed upon discovery).