Sometimes, {{The Hero}}es are faced with a seemingly insurmountable enemy. Be it a MightyGlacier that absorbs damage like a truck or a FragileSpeedster that dodges attacks with lithe grace, some enemies are hard to defeat with standard tactics. They can generally be defeated through brute force, but it's very difficult. The smarter and much easier way to defeat such a foe is to employ clever strategy and some often unintuitive insight.

An OutsideTheBoxTactic is a simple or otherwise overlooked tactic that is particularly effective against a certain monster or type of monster. It is a closely related to an AchillesHeel; the difference being that this weakness is not the only reliable way to defeat such a foe. A foe susceptible to an Outside The Box Tactic is still vulnerable to other tactics, but is very weak to this particular strategy. It is primarily a RolePlayingGame trope, but may be found in other types of games as well.

The most famous and common example involves the use of healing magics or other restorative items to harm the undead, examples of which should be listed under ReviveKillsZombie. If this particular application of a technique is the only place where it is effective, it may be NotCompletelyUseless. If the method was unintended by the game developers, it may be the result of a GoodBadBug. If the method of attack actually involves not attacking the opponent at all, it becomes SheatheYourSword. If it's not hinted at in any way, yet is the only way to defeat the foe, it may also be a GuideDangIt. If it's not the only way to defeat a foe, but it requires ForcedLevelGrinding to defeat it otherwise, it may be commonly thought of as ThatOneBoss or a BeefGate. Outside-The-Box Tactics are often necessary to defeat a PuzzleBoss or the FinalExamBoss.

Contrast LogicalWeakness, when it's immediately apparent what needs to be done.
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!!Examples:

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[[folder: Video Games ]]

* In ''[[VideoGame/PLATOMoria Moria]]'' and some versions of ''VideoGame/{{Angband}}'', the spell "Turn Stone to Mud", normally used for digging new passages, can also be used to devastating effect against stone-based monsters such as golems. ''{{Nethack}}'', a distant cousin, lacks a similar direct equivalent of the Dungeons & Dragons ''stone to earth'' spell, but it ''does'' have "stone to flesh", which makes stone golems much easier to kill -- and also, when used on rocks or boulders, produces prodigious amounts of perfectly edible meat, which non-vegetarian characters can use to stave off starvation.
* In ''VideoGame/DragonQuest'' games, Holy Water is supposed to be used to help avoid RandomEncounters. It can also sometimes be used in battle, but its only effect is to deal a pathetic amount of damage. However, it works just as effectively against [[MetalSlime Metal Slimes]] as any other enemy, and their low HP makes using Holy Water against them a good strategy.
* ''Franchise/FinalFantasy'':
** In the original NES version of ''VideoGame/FinalFantasyI'', Tiamat can be killed with the instant death spell BANE.
** In ''VideoGame/FinalFantasyIV'', the Wall (Reflect) spell is integral to defeating Asura, who heals herself twice, at the end every round, in addition to attacking your party. The catch? You have to cast Wall on her. That way, when she attempts to heal herself, Wall reflects it heals your party instead. Asura inflicts insane amounts of damage and recovers 2,500-3,300 HP per recovery spell, making her borderline impossible to defeat without this trick.
*** ''Final Fantasy VI'' also had the spells Rasp and Osmose, which depleted an enemy's magic points (the latter also restored yours by the same amount). Some enemies were noted ([[GuideDangIt though only at one spot in the entire game]]) to be inherently magical, and unable to maintain their forms if their MP was depleted. You thus had the option of either depleting their hit points or magic points to defeat them; in the case of several that had last-ditch attacks when out of hit points (including ThatOneBoss), removing their magic was the wiser (or sometimes faster) option.
** ''VideoGame/FinalFantasyV'':
*** The only practical way to defeat BonusBoss Odin is to use petrification attacks, which will instantly kill him.
*** The Mimic. He'll attack with whatever you attack him with. The key to victory: Do nothing.
*** There's an endgame boss that can learn any Blue Magic spell you cast on it and then cast it back at you. Exploder is a Blue Magic spell that kills that caster and does their current HP in damage: just cast it on the boss and watch it gleefully use its new toy to kill itself.
** In ''VideoGame/FinalFantasyVI'', there is the spell "Vanish". It temporarily causes all physical attacks to miss, but guarantees the next magical attack to hit. [[OneHitKill Death and X-Zone]], normally {{Useless Useful Spell}}s, suddenly become much more appealing. This combo will fail only on enemies immune to Vanish -- since Vanish is supposed to be a ''positive'' effect, there are very few of these. It's also supposed to fail on enemies immune to instant death, but "Vanish = magic succeeds" is checked before "immune to death = death spells fail"; this was fixed in [[VideoGameRemake the GBA version]].
** In ''VideoGame/FinalFantasyVII'', the Demi spell is surprisingly effective against Emerald Weapon. Demi is a low-level Gravity spell, that does damage equal to 25% of the target's current HP. On most common enemies, it's a waste of time. Most bosses are immune. But Emerald Weapon is not, and, until you whittle his HP down, it can do the 9,999 damage cap to him.
** In ''VideoGame/FinalFantasyX'', the final boss can be easily killed by using Zombie and a phoenix down.
*** You can do the same with one previous boss, who is undead to begin with.
** In ''VideoGame/FinalFantasyXIII'', bosses are immune to Death... except the final boss, when it's staggered.
** And in ''VideoGame/FinalFantasyTacticsA2'' the Ranger class gains the "Mirror Item" skill, which changes it from ReviveKillsZombie to [[OneHitKO Revive Kills Everything Except Zombie]], as well as the more obvious inversions such as making Potions deal damage. And Remedies (normally a cure-all) now inflict ''everything''.
* In the ending chapter of ''[[VideoGame/FireEmblemTellius Fire Emblem: Radiant Dawn]]'', the [[ImplacableMan Black Knight]] can be easily beaten by forgoing use of the InfinityPlusOneSword in favor of [[ArmorPiercingAttack using a common]] [[DropTheHammer Hammer]].
* The Berserker in ''VideoGame/LegendOfLegaia'' can be instantly killed via the Nighto spell. It is the only boss vulnerable to this tactic, and is ThatOneBoss otherwise. It is FridgeBrilliance when one considers that Nighto inflicts the Confuse status.
* Get the hit just right, and it's possible to OneHitKill the final form of ''VideoGame/TheLegendOfZeldaLinksAwakening's'' final boss with the boomerang.
* Several enemies in ''VideoGame/MetroidPrime 3'' can be killed in a single strike of the Nova Blaster augmented by the X-Ray Visor, due to the limitations of their Phazite armor.
* ''VideoGame/MarioAndLuigiSuperstarSaga'' features the Trunkle boss, which dies to one or two hits of the Chopper Bros. attack to the forehead.
* In ''SuperMarioRPG'', due to a [[GoodBadBugs design quirk]] Exor is vulnerable to Geno's OneHitKill attack, which all the other bosses have ContractualBossImmunity against.
* ''VideoGame/MegaMan2:''
** Mecha Joe walkers are very vulnerable to air shooter and several HumongousMecha are vulnerable to boomerangs.
** During the BossRush portion of the same game, Metal Man dies to one hit of [[PowerCopying his own weapon]].
* The ''VideoGame/MegaManX'' series continues the trend of its predecessor series. While many bosses have {{Logical Weakness}}es, the Launch Octopus and Flame Mammoth both have one of these - the boomerang attack can cut off Octopus' tentacles and prevent him from using his homing and tornado attacks, as well as being able to cut off Mammoth's trunk so he can't throw around globs of oil he can set on fire and turn them into pillars of fire. You can also [[CycleOfHurting stunlock]] Spark Mandrill and Sting Chameleon.
** There's also [[ShockAndAwe Web]] [[GiantSpider Spider]] from ''X4''. The Twin Slasher does more damage than normal to him, but in order to hurt him ''really hard'', you should fire it at the web he's hanging from, cutting it. He'll drop and [[NotTheFallThatKillsYou go splat on the ground]] for massive damage.
* The [[FinalBoss Final Bosses]] in the {{VideoGame/MOTHER}} series can't be defeated by typical RPG methods.
** ''VideoGame/{{MOTHER 1}}'': You defeat [[spoiler: Giegue by singing the lullaby his adoptive mother sang to him as a baby]].
** ''[[VideoGame/EarthBound MOTHER 2 / Earthbound]]'': Giygas is defeated by [[spoiler: using Paula's almost useless "Pray" command to make everybody you've helped in the game stop and hope that you're safe.]]
** ''VideoGame/{{MOTHER 3}}'': [[spoiler: The Masked Man remembers that he used to be Claus when his dead mother's ghost begs him and Lucas to stop fighting. He sends a [[OneHitKill lightning attack]] at Lucas. [[DrivenToSuicide Lucas has an item that reflects lightning.]]]]
* Some [[ThatOneBoss otherwise difficult]] bosses in ''VideoGame/{{MOTHER 3}}'' have some vulnerabilities to certain techniques.
** The Fierce Pork Trooper. Sure, he's kinda weak against fire, and it ''is'' possible to defeat him with standard melee and PSI attacks, but he becomes much easier to defeat by employing his weakness: DCMC merchandise. Show him some stuff featuring his favourite rock band, and he becomes unable to attack for several turns, turning this into a much easier battle.
** The Barrier Trio is a normally difficult boss who [[TotalPartyKill throws high-level PSI at your entire party every single round]], when all methods of healing at this point will only affect one party member. However, if you constantly lower their defense with the Tickle Stick and Defense Down, they ''might'' attempt to bring their Defense back up, slowing down their barrage of attacks.
* In ''VideoGame/OdinSphere'', Onyx can be glued to the spot with a normally useless "Ooze" potion to stop ThatOneAttack. Since he's so damn big and an Ooze is so small and moves back and forth slowly, Onyx won't be able to do a damn thing except watch his HP go down as you start wailing on him.
* It's a running gag that the final boss, Dhaos, of ''VideoGame/TalesOfPhantasia'' is susceptible to the ''Indignation'' spell. In cameo appearances in later games, he dies to one use of the spell.
* Gespent, a sub-boss in ''VideoGame/WildArms3'', can be killed with a single use of the ''Requiem'' spell.
* In ''VideoGame/DragonQuestIII'', Zoma (the game's final boss) can be severely damaged by healing spells or Medical Herbs. In fact, this is the most effective way to attack him. He has to be weakened first with the Sphere of Light, though. [[GuideDangIt There is absolutely nothing in the game that suggests this is possible]]. Even the ''complete walkthrough'' provided in the NES manual didn't say anything.
* The Dominate special ability in ''VideoGame/MassEffect2'', which lets you control organic enemies so they'll attack their allies (basically the equivalent of the normal AI Hacking power), is also inexplicably able to kill husks instantly.
* Inferno, the final boss of ''[[SoulSeries Soul Calibur 2]]'', is normally ThatOneBoss... unless you exploit his weakness. Surprisingly for a flaming creature, he has ''no'' ability to avoid throws, and they take off much more damage than any other attacks.
* ''VideoGame/TheWorldEndsWithYou'': Two major flaws of the Time Bomb psych is that it takes a while to actually explode and when it does, any enemy hit flies into the air. Well, the [[BossInMookClothing elephants]], including the BonusBoss one, and both forms of the FinalBoss are slow/immobile and cannot fly in the air. The Time Bomb psych will utterly destroy them.
* ''VideoGame/TeamFortress2'': Spies with the Dead Ringer can fake their own deaths while implementing InterfaceScrew to fake out the attacker's killfeed. Weapons with unique/altered killfeed messages like the Holy Mackerel won't show their unique message, tipping off the attacker to the Spy's trickery.
* Like most bosses in ''VideoGame/GoldenSunDarkDawn'', the Ancient Devil is [[UselessUsefulSpell immune to status effects]]. However, its main gimmick is its power to [[BrainwashedAndCrazy enchant your player characters into assisting it]], and ''they'' can be hobbled by status effects. Since the Devil will just enchant someone else if its current ally drops, this is a better way to minimize losses.
* Jormungandr, the second boss of ''{{VideoGame/Magicka}}'' is a giant snake of the burrowing flavor. Normally his head is the only weakpoint, which he holds above the ground when not attacking. While it's not to difficult to hit his head during the attack frames, it's far easier to use a shield spell before he comes up or burrows again because he takes collision damage. Not only does this do more damage than your average beam spell, it also stuns him briefly and then forces him back under ground before he can attack
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[[folder: Non Video Game Examples ]]


[[folder: Anime & Manga]]
* This can occasionally come up in ''Manga/OnePiece,'' [[HeartIsAnAwesomePower along with unexpected strengths,]] when a Devil Fruit power sometimes provides an unforeseen advantage against another power. One of the more prominent examples would be low-tier villain Mr. 3, whose power to create objects out of wax ends up temporarily providing the single best countermeasure against poisonous ImplacableMan Magellan.
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[[folder: Comic Books]]
* In ''Comicbook/{{X-Men}}'', Sebastian Shaw absorbs any kinetic energy directed at him, even a bullet, so Storm covers him in snow, [[YouFailPhysicsForever which actually saps his energy, due to cold being a lack of said energy.]]
** Ironically, 15ish years later the X-Man Bishop -- whose powers are similar to Shaw's -- would charge himself up ''by using snowfall''.
*** Not really. Bishop can absorb any kind of energy directed at him, Shawn can only absorb kinetic. This means that while Shanw can become stonger by beating a wall (at least until his powers charge out) Bishop can absorb energy even if he doesn want to (classic point was when Magneto used his powers to stop X-Men from moving by controlling their iron molecules in blood stream, but Bishop countered this by absorbing his magnetic powers).
* In ''ComicBook/{{Invincible}}'' the main character faces a villain with powers similar to the X-Men character mentioned above; the way the main character wins is [[spoiler: continues punching the badguy until he's been overloaded with so much energy it travels through the floor vaporizing his family and emotionally crippling him]]
* In ''{{Knightfall}}'', Shondra Kinsolving had the ability to heal using HealingHands, but when combined with her stepbrother, she and he could kill anyone from afar by healing them ''too much'', putting the victim's glands and nervous system on fatal overdrive.
* In an issue of [[JusticeLeagueOfAmerica JLA]], the League fight an Amazo who has the powers of the whole League...on a conceptual level. Every time they bring in more reinforcements, Amazo gets more powerful. The Atom works out how to beat him; he tells {{Superman}} to officially disband the League. Amazo loses all his powers and shuts down.
* ComicBook/TheAvengers once fought a similar robot. They beat it by exposing it to CaptainAmerica, and it absorbed his fundamental goodness. Then it declared that the Avengers were good guys and it didn't want to fight anymore, regardless of the wishes of its creator.
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[[folder: Film]]
* [=AT-AT's=] in the ''Franchise/StarWars'' series have thick armor impervious to the blasters on rebel fighters. However, due to their being very top-heavy, a simple harpoon and tow cable can bring them down with ease. They're also much less heavily armored, and therefore more vulnerable, in the ventral aspect, though a competent commander will deploy them in such fashion as to obviate any potential risk thus caused; they're not particularly quick, so a long advance to contact provides more than enough time for their heavy forward-mounted guns to flatten anything which might shoot up at them from below. (Shot-down stray Jedi, of course, notwithstanding -- but it'd take a whole lot of them, even at a rate of one Jedi and one thermal detonator per AT-AT, to make a real difference in any kind of serious battle.)
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[[folder: Literature]]
* In ''Literature/TheWonderfulWizardOfOz'', water is this to the Wicked Witch of the West.
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[[folder: Live Action TV]]
* ''Series/StarTrekTheOriginalSeries'' the characters had to deal with an alien that fed off of anger. The Starfleet officers and the Klingons puts aside their differences and laugh it off.
* ''Series/StarTrekTheNextGeneration'', there was a Vulcan device that turned people's anger into a weapon. To counter this, the characters calm themselves down.
* This thinking is what ''Series/BuffyTheVampireSlayer'' is known for, from creating a Slayer army to defeat the FinalBoss to the time she found out whether a demon who claimed to be invincible wasn't rocket proof.
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[[folder: Tabletop Games]]
* ''TabletopGame/DungeonsAndDragons''
** Casting ''regenerate'' on an Eye of Gruumsh (a one-eyed, mad orc fighter) restores its other eye and negates its magical abilities as well.
** Encounter a badass villain wearing [[ElementalCrafting Dragon Scale armor?]] Cast Resurrection ([[ContinuingIsPainful True or otherwise]]) on the armor, and let him [[OutsideContextVillain deal with the angry dragon]] while you slip past.
** Transmutation school Wizards are the king of this trope. Flesh to Stone, Stone to Mud, Purify Water, anyone?
* ''TabletopGame/{{Exalted}}'' has a [[FunctionalMagic Charm]] (Order-Affirming Blow) that undoes Shaping effects. Guess what? TheFairFolk use shaping effects to create their bodies. OneHitKill.
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[[folder: Visual Novels]]
* In ''VisualNovel/FateStayNight'', Saber is representative of [[spoiler:King Arthur Pendragon]]. She is vulnerable to items and spells that harm [[spoiler:dragons]] as a result.
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[[folder: Western Animation]]
* ''WesternAnimation/JusticeLeagueUnlimited''
** In the episode "Hawk and Dove", the Annihilator defeats much of the League by feeding off aggression and hostility. When [[ActualPacifist Dove]] faces the machine and neither attacks it nor fights back in self defense, the machine shuts down.
** In the same vein, the android AMAZO mimics both the principal characters' superpowers and weaknesses. After he obtains Superman's strength, he also obtains his weakness to kryptonite. He [[SubvertedTrope quickly evolves past this weakness though]]. Then the trope is invoked a second time as the Martian Manhunter deliberately lets AMAZO copy his powers... which include telepathy, which it uses to read Lex Luthor's mind and discover how he tricked it into fighting the League in the first place.
* The ''SamuraiJack'' episode "Jack vs. Mad Jack" has Jack fighting a clone spawned from his irrational anger. At the conclusion, he catches on, steps back and meditates. With his anger calmed, the clone's power cuts off and it dissipates.
* When Trixie shows up for revenge and curb-stomps Twilight in ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', Twilight's only chance to fight back is some TrainingFromHell to become as powerful as Trixie. [[spoiler:However, being well-aware that she can't match her power, Twilight instead uses trickery and stage magic to defeat her.]]
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[[folder: Real Life]]
* To some extent, the evolution of strategy and tactics is one series of these after another. Tactics constantly evolve to adjust to social, political, and technological factors, and in turn affect them in turn. One needs to look only at World War I: the deadlock of the trenches led to the development of quickfire artillery barrages, squad and platoon assault tactics, armored advances, all of which would have been unimaginable to all but the most prescient officers in 1914. The success of the tank led to entire strategies built around it that would dominate the Second World War and the Cold War. What seemed new and outside-the-box in the last war could quickly turn into standard operating procedure in the next.
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