History Main / EnemyExchangeProgram

** Over-using the Salvage Corvettes can lead to problems in the last level of the single-player campaign. In a previous level, you are faced with a large number of enemy ion cannon frigates. By themselves, ion cannon frigates aren't dangerous to fighters and corvettes, so you can fairly easily capture one. Then rinse and repeat. However, once the final mission starts, you are immediately besieged on three sides by a force whose strength is directly proportional to yours. So if you happen to have captured 30 or so ion cannon frigates, thinking that this will make your endgame a cakewalk, you will quickly find yourself overwhelmed by a much stronger enemy force.
** The main antagonist of ''Cataclysm aka Emergence,'' the aptly-named Beast, has this as its hat and it's ''horrifyingly'' good at it. As the Beast is a nasty combination of TheVirus and GreyGoo "exchange" here means less dragging the vessel back to a shipyard for retrofit and more bombarding the vessel with Beast particles until the vessel is assimilated and controlling it with bio-circuitry [[HumanResources made from the bodies of the crew.]] The effect is treated more like DemonicPossession, both mechanically and in-universe.

*** Even then, in Brood War during one Protoss mission [[spoiler:you are given a free Zerg base from Kerrigan to aid your troops]], and various missions have a limited use of units from different races under your control.
*** The Zerg get an aversion though: an infested command center is acquired by beating an enemy command center to the red, then getting a Queen unit to the building before it explodes. For your trouble, you get an entirely different building that makes [[ActionBomb Infested Terrans]], a unique unit which is also far different from what a Command Center usually produces.
** ''VideoGame/{{StarCraft II}}'': There is an achievement called Zerglot. While playing as Zerg against a Protoss opponent, use an Infestor unit's mental parasite ability to take temporary control of an enemy probe, which is the Protoss worker unit. While the probe is still under your control, build a Nexus, the Protoss Command Building. Then continue building Protoss buildings with probes built at the Nexus until you can build a Zealot, and then build it. This earns the Zerglot achievement. It is possible to do this in any game mode, but playing against the AI makes it much easier. It is also possible to do this with Terran units by capturing an SCV, but it will either have to be captured again by different Infestors, or multiple ones will have to be captured sequentially to build a Command Center.

** Any unit that can build or repair can capture enemy units and structures, though is generally easier to just salvage them. Becomes extra fun when you manage to steal an enemy's engineer when they're a different faction than you. Since a single engineer with some resources can construct everything needed to make an entire army, one can then build practically ANYTHING normally reserved for your enemies with a bit of time.

*** Similarly for the Rebels, Chewbacca can take over nearly any enemy vehicle (including ''AT-ATs''), and R2-D2 can hack into enemy turrets to convert them.

* In the MMOFPS ''Videogame/PlanetSide 1'', each of the three empires has several unique vehicles that only they can build. However, capturing both of said empire's home continents allows the conqueror to freely build those empire-specific vehicles. For example, a [[PeoplesRepublicOfTyranny Terran Republic]] player could build, say, a [[MachineCult Vanu Sovereignty]] [[HoverTank Magrider]] and a [[MegaCorp New Conglomerate]] [[HumongousMecha Peregrine]] if his empire is currently in control of all three empire's home continents. Players with the Advanced Hacking certification and a REK tool can hack enemy vehicles to their own side - and simultaneously kick out the occupants - allowing them to get in a gun to wreak havoc, or more commonly, just deconstruct it to prevent the enemy from re-hacking it.

** It's done so frequently in the franchise that it sometimes becomes a quick-victory tactic. The oldest and most common method is to send an Engineer into an enemy building, allowing you to produce side-specific infantry and equipment with it. Newer games bring newer methods. ''[[VideoGame/CommandAndConquerTiberianSun Tiberian Sun]]'' introduced [[HeroStoleMyBike abandoned vehicle hijacking]], ''[[VideoGame/CommandAndConquerGenerals Generals]]'' expanded this to include [[SnipingTheCockpit killing the pilots of enemy vehicles]], ''[[VideoGame/CommandAndConquerRedAlert2 Red Alert 2]]'' had varying strengths of [[MindControlDevice wireless mind control]], and as of ''VideoGame/CommandAndConquerRedAlert3'', there's [[EveryManHasHisPrice bribing]].

** ''VideoGame/RedAlert2'': The Allies' IFV changes its weapon depending on the type of infantry loaded inside. This includes non-Allied infantry, who get their own unique turrets and effects.

** ''VideoGame/RedAlert3'': Capturing and using enemy buildings and units is often a vital part of gameplay, as non-faction units can often cover weaknesses in the faction's units (such as the Imperial fighter being better suited for escorts as it doesn't need to retreat and reload, or the Soviet ground-attack chopper being suited for both anti-infantry and anti-vehicle, or the Allied IFV providing vehicle repairs on the move).

** ''Literature/FateZero'': Berserker's second Noble Phantasm, "Knight of Owner" allows him to appropriate stuff and [[turn it into MagicEnhancement low-ranked Noble Phantasms]] -- basically, anything from a street lamp to a stolen fighter jet. The only requirements for this to work are that Berserker regard said stuff as a weapon and that he has to physically touch it (his combat tentacles come in handy by extending his reach).

Compare MonsterAllies. See TheEnemyWeaponsAreBetter when this is limited to the weaponry instead of the soldiers wielding them and VehicularTurnabout specifically for vehicles. Has not to do with exchanging enemy agents, that's PrisonerExchange. Related to BrainwashedAndCrazy. See also StrategicAssetCaptureMechanic.

* ''Manga/MyHeroAcademia'': The BigBad's Quirk allows him to steal, store, and transfer Quirks. He employs it to steal both powerful and support-type Quirks from the heroes and his criminal rivals. Then, he either keeps them for himself or gifts them to his underlings as a reward. As of lately, he has taken on reinforcing corpses with all sorts of Quirks to create mindless Nomus. This trope is kind of {{lampshaded}} in the Quirk's name, which also serves as the villain's [[RedBaron alias]]: All for One.

Compare MonsterAllies. See TheEnemyWeaponsAreBetter when this is limited to the weaponry instead of the soldiers wielding them and VehicularTurnabout specifically for vehicles. Has not to do with exchanging enemy agents, that's PrisonerExchange. Related to BrainwashedAndCrazy.

** In a sense, this is what the Nara Clan's [[CastAShadow Shadow Manipulation]] techniques do. The Kagemane doesn't override the victim's sense of self, it just forces them to mimic the caster's movements because it latches on their chakra system. This is mostly a capture & containment tactic but can also be used to make the target fire projectiles or attack their allies.

** Aka Midoriya's Quirk is called Assimilation. She can rip pieces of her body off and then insert them into a person's bloodstream via a cut. Once in there, she completely takes over her victim's body -- they are not brainwashed, they are controlled by Aka's conscience like puppets. During villain attacks, she uses her Quirk to turn the tides in her family's favor by assimilating the most powerful Nomus and villains.
** The Sky Pirates debut the criminal scene by infiltrating the Midoriya Foundation to steal a Chaos energy-fueled, flying ship from the facility's labs. Other than serving as the villain team's namesake, the purpose is to obtain a base of operations that cannot be reached by Quirks and is undetectable by radars. In truth, this is a {{subver|ted}}sion because the Sky Pirates were created and funded by none other than Izuku Midoriya, so the villain team and the Midoriya Foundation are only enemies in the eyes of the public. This move [[ExploitedTrope is meant]] to thwart any suspicion about the two organizations being related.
** Engineer Rorou Con's Quirk is called Ownership and grants him the ability to "own" any nonliving object. In other words, Rorou gains complete control of the object's properties and functions. This gets especially useful when the Sky Pirates are raiding some rival criminal organization's base.

* ''Fanfic/IDontRunAnOrphanage'': The Sky Pirates debut the criminal scene by infiltrating the Midoriya Foundation to steal a Chaos energy-fueled, flying ship from the facility's labs. Other than serving as the villain team's namesake, the purpose is to obtain a base of operations that cannot be reached by Quirks and is undetectable by radars. In truth, this is a {{subver|ted}}sion because the Sky Pirates were created and funded by none other than Izuku Midoriya, so the villain team and the Midoriya Foundation are only enemies in the eyes of the public. This move [[ExploitedTrope is meant]] to thwart any suspicion about the two organizations being related.

* ''VideoGame/MenOfWar'' thrives on this trope. Every vehicle requires a crew of one to five soldiers. You can shoot down the crews of machine gun emplacements, mortars, field guns, and artillery, obviously. However, you can also force crews out of tanks with a well-placed shot or anti-tank grenade (if it disables the turret), then repair it, put in your own crew and turn it loose on the enemy. In the case of open-topped vehicles, you don't even need specialized munitions - simply chuck in a standard frag grenade. The series should be called Grand Theft Tanks, to be honest.

* ''Franchise/FateSeries'': When a Master is defeated but the Servant is still around for some reason -- usually, they are in that little timespan between the Command Spells having been used up and the Servant disappearing, a different Master can bind them with their own Command Spells if both parties agree. Command Spells can also be transferred between Masters and, in some cases, even stolen.

* [[UsefulNotes/TheGloryThatWasRome The Ancient Romans]] tended to recruit from both recently conquered nations, be they "allies" that were subordinate to Rome or outright conquered, and part-time hostile Germanic tribes to supplement their forces and, after Marius' reform turned Roman citizen forces into heavy infantry only, provide badly needed specialists in other fields of warfare (Balearic slingers were particularly appreciated, as Rome had learned the hard way how lethal they could be when they were on the other side of UsefulNotes/ThePunicWars). This also had the benefit of having the soldiers [[GoingNative exposed to Roman culture for years until they are culturally assimilated]], increasing their control of conquered areas and weakening Germanic will to fight them - assuming the Germanic mercenaries didn't decide to ditch their original people and live in Roman land after earning citizenship through their service.

Compare MonsterAllies. See TheEnemyWeaponsAreBetter when this is limited to the weaponry instead of the soldiers wielding them and VehicularTurnabout specifically for vehicles. Has not to do with exchanging enemy agents, that's PrisonerExchange.

* ''Anime/PuellaMagiMadokaMagica'': {{Zigzagged}} as it's not done to an actively hostile party but a neutral, non-allied one. Due to the lack of offensive potential of her magic, Homura steals all sorts of weaponry (and even vehicles) from Japan's Armed Forces and Yakuza to use against the [[EldritchAbomination witches]]. She's commonly seen with pistols and assault rifles, but if the necessity arises, she pulls out grenades, machine guns, rocket launchers, and even tanks from her HammerSpace.

* Master of Orion II had several features centered around capturing alien ships and populations. Capturing Antaran ships in particular would provide a major technological advantage. Some players would even ''exterminate their own population units'' and replace them with captured aliens that had superior environmental tolerances or resource-production!
* While there are a few provinces in ''VideoGame/MedievalTotalWar'' that specialize in a unit and will produce them for anyone, most troop types are tied to the factions. So if your English crusader army captures Egypt the locals suddenly figure out how to grow yew trees in the desert but forget how to herd camels.
** The British campaign in ''VideoGame/MedievalIITotalWar: Kingdoms'' changes this to allow you to recruit this provinces native units for as long as the native culture is dominant there. After it is assimilated into your culture, it can only produce your normal units. This gives you a choice of whether you want certain cool units you can't normally get with the risk of rebellion in the province or safety but losing out on the units.

r* ''VideoGame/CommandAndConquer'':

[[folder:[=MMORPGs=]]]
* In the MMOFPS ''Videogame/PlanetSide 1'', each of the three empires has several unique vehicles that only they can build. However, capturing both of said empire's home continents allows the conqueror to freely build those empire-specific vehicles. For example, a [[PeoplesRepublicOfTyranny Terran Republic]] player could build, say, a [[MachineCult Vanu Sovereignty]] [[HoverTank Magrider]] and a [[MegaCorp New Conglomerate]] [[HumongousMecha Peregrine]] if his empire is currently in control of all three empire's home continents. Players with the Advanced Hacking certification and a REK tool can hack enemy vehicles to their own side - and simultaneously kick out the occupants - allowing them to get in a gun to wreak havoc, or more commonly, just deconstruct it to prevent the enemy from re-hacking it.
[[/folder]]

** The sequel adds the caveat that the converted unit is immediately turned into the converter's era-appropriate version if they're at different TechnologyLevels (e.g. a prehistoric priest converting a modern mortar soldier gets an archer, a modern priest converting a spearman gets a machine gunner), with cavalry/tanks being replaced by their highest/lowest tech level equivalent. Even more jarring is the fact that they take on the appearance of the converter's civilization as well, most dramatically seen with the all-black African civilizations

[folder:[=MMORPGs=]]]

* ''VideoGame/CommandAndConquer'':

* Possibly the oldest game that does this is ''VideoGame/PopulousII'', which allows you to place "baptism fonts" with water magic, which convert troops from one side to the other (and back). The prequel, ''VideoGame/PopulousTheBeginning'' (the earlier Populous games are god games, and this one is a straight RTS where the plot involves becoming a god) has the enemy-converting priest as one of the basic troops.

** ''VideoGame/ZSteelSoldiers'' has an early level where plot-wise you're attempting to build up your forces and technology (as command hasn't sanctioned your actions) by using a hacker to take control over a small enemy base before assaulting the larger one. In general gameplay the hacker can be useful but they're weak and easily destroyed by gun-emplacements.





* ''VideoGame/SevenKingdoms'' allows you to easily reproduce each race's buildings and units, with the exceptions of the powerful Seat of Power, which can only be built if you have the respective scroll (and each human nation starts with only one). However, human players can't build any of the demonic Frythans structures even if they control some of their units, but it works the other way around. (Getting a large enough number to operate the structures is another issue entirely, as well as keeping them from rebelling).
* ''VideoGame/{{Homeworld}}'' has the Salvage Corvette that can pick up small enemy craft or latch onto larger ships and drag them back to your Mothership, where presumably the enemy crew is subdued (or worse). The enemy ship is then re-launched with a friendly crew, allowing you to control it. The GameBreaker is that this allows you to exceed the ArbitraryHeadcountLimit, potentially giving you a fleet far larger than you could possibly build on your own and making later levels trivial.
** Over-using the Salvage Corvettes can lead to problems in the last level of the single-player campaign. In a previous level, you are faced with a large number of enemy ion cannon frigates. By themselves, ion cannon frigates aren't dangerous to fighters and corvettes, so you can fairly easily capture one. Then rinse and repeat. However, once the final mission starts, you are immediately besieged on three sides by a force whose strength is directly proportional to yours. So if you happen to have captured 30 or so ion cannon frigates, thinking that this will make your endgame a cakewalk, you will quickly find yourself overwhelmed by a much stronger enemy force.
** The main antagonist of ''Cataclysm aka Emergence,'' the aptly-named Beast, has this as it's hat and it's ''horrifyingly'' good at it. As the Beast is a nasty combination of TheVirus and GreyGoo "exchange" here means less dragging the vessel back to a shipyard for retrofit and more bombarding the vessel with Beast particles until the vessel is assimilated and controlling it with bio-circuitry [[HumanResources made from the bodies of the crew.]] The effect is treated more like DemonicPossession, both mechanically and in-universe.
** Homeworld 2 also allows for capturing with the Hiigaran Marine Frigate and its Vaygr equivalent. The frigate flies up to an enemy vessel and launches a boarding party to take over the ship. However this is much less useful than in the first game as it's a lot harder to capture enemy ships since the marine frigates are easily killed, not to mention that any ships you've captured will lose their upgrades and you you can't bypass the unit cap.
* Played straight and averted in the ''VideoGame/{{Warlords}}'' series. In the first two games, once you occupy an enemy city (without pillaging or sacking it) you can produce any units that the enemy could in that city, including special units that are specific to the enemy side and otherwise unavailable to you. In the third game captured cities cannot produce those special units unless your side is already capable of doing so.
* Averted in ''VideoGame/WarlordsBattlecry 2'', whereas the hero can convert enemy buildings, but the buildings can not be used to build units. They add to your army limit though.
* ''VideoGame/DawnOfWar'', from the ''TabletopGame/{{Warhammer 40000}}'' continuity: Dark Crusade'' introduced the Necron Lord Destroyer, which could "possess" enemy vehicles and convert them to your side. When these vehicles are destroyed, the Lord Destroyer pops out damaged but "alive". Seeing as you could only build a maximum of two of these, though, using this is situational.
* ''VideoGame/HaloWars'' gives the UNSC access to SPARTAN {{Super Soldier}}s, who have various abilities. One of these includes the power to hijack enemy vehicles, just like they can in the ''Franchise/{{Halo}}'' FPS games. They can't capture "elite" units such as the ''Vulture'' gunship (UNSC), which is an air unit anyway, and the Covenant Scarab (which is normally controlled by many beings).
* Averted in ''VideoGame/StarTrekArmada'': to capture an enemy ship, its shields must be disabled and then boarding parties must be beamed onboard, taken from the capturing ship's crew complement. The boarding crew will invariably take casualties as well, and ships have a minimum crew requirement before they will operate at full efficiency. The Borg, however, play it straight by holding ships in a tractor beam and transporting the enemy crew ''off'' to be assimilated, though they can also capture ships the 'standard' way.
** Also played somewhat straight in that capturing an enemy construction ship allows you to access the entire tech tree and build a complete fleet of ships of the construction ship's original race. They will, however, be crewed by members of your own race, often with hilarious results such as a Romulan-manned Borg cube responding with, "Warbird reporting..." when selected because the sound bites for a given unit type (in this case "battleship") are simply transferred straight across (in this case from the Romulan Warbird to the Romulan-manned cube) to all "battleship" type units manned by your race without regard to whether they are fitting or not... Also, by the way, only the Borg's Assimilator unit transports the enemy crew off their ship to be assimilated (where they are either added to the Assimilator's crew or added to your general crew pool if the Assimilator has a full compliment) and it does not actually hold the enemy ship in place. The Borg cube's holding beam does hold enemy ships in place, but it just does exactly what the transporter does except on a larger scale (more Drones are transferred per second than with the transporter) and able to do it through enemy shields... Incidentally, capturing an Assimilator as another race does not remove its special ability. This has the hilarious side-effect of having, say, a Federation-manned Assimilator "assimilating" enemy crew, including the Borg player you stole it from in the first place.
** The sequel averts this with the Species 8472, which have all their bio-ships piloted by a single being. They're also immune to assimilation. Played straight with everyone else. In fact, the game introduces raider ships, whose function is specifically to capture enemy ships. They have a special type of attack command that fires weapons at the enemy until their shields are down and then starts transporting elite marines aboard. A Klingon ship also has boarding pods that bypass shields.
* ''VideoGame/{{Warzone 2100}}'' had the NEXUS link turret, which infected enemy units with a virus that made them fight for your side. Somewhat subverted that in single player, it's mostly the enemy NEXUS faction using it on ''you'', and by the time you research the link turret yourself, NEXUS has the Resistance Circuits tech (also obtainable by the player) that makes the link turret ineffective.
* ''Videogame/StarWarsGalacticBattlegrounds'': Jedi and Sith Knights and Masters (well, Sith Lords anyway) can convert units and buildings. Of course, because 75% of the differences between the sides' units are cosmetic, this is only really useful for stealing unique or expensive units, protecting the Jedi in question, or taking advantage of racial special abilities such as the Gungan frigate's ability to submerge. Unlike the ''VideoGame/AgeOfEmpires'' priests and monks upon which the engine is based, however, Jedi and Sith are durable enough to see front-line combat, though their prohibitive cost limits their effective use.
* ''VideoGame/MachinesWiredForWar'' features allow you to take over enemy buildings as well as steal unit design plans, also the Judas warlord that can convert enemy units to your side.
* ''VideoGame/AztecWars'': Each of the nations has a different set of buildings and units. If you conquer a different nation's base, you can construct their buildings and units there. In fact, some of your ''own'' units can only be built if you control a building that can only be constructed by a different nation.
* In ''VideoGame/RiseOfNations'', the Spy is capable of converting enemy units to the other side using the ability ''Bribe''. However, the normally invisible Spy is revealed after the ability and is partially revealed during the casting (usually during this time they are insta-killed by the ''Counter Intelligence'' ability). Apparently, the vanilla "Rise Of Nations" had the Russians produce spies that don't reveal after using Bribe, so it was kind of a GameBreaker.
* 8-bit ''VideoGame/NetherEarth'' may be the oldest example. The whole plot of the game is about capturing alien bases and factories to build robots to capture more bases and factories to kick aliens off the asteroid.
* In ''VideoGame/CompanyOfHeroes'', many weapons like mortars and heavy machine guns require crews to operate. If your troops manage to kill the crew of a weapon without destroying it, they can pick it up and turn it against its original owners.
** ''Company Of Heroes 2'' extends this to vehicles, which may be abandoned by their original crews instead of being destroyed outright. Any infantry unit of sufficient size may then capture them, though they then require significant repairs before once again being battle ready.
* In the ''VideoGame/HegemonySeries'', every city has a culture and can only recruit units of that culture. They'll cost extra, but you'll have enemy units.
* ''VideoGame/MenOfWar'' thrives on this trope. Every vehicle requires a crew from one to five soldiers. You can shoot down the crews of machine gun emplacements, mortars, field guns, and artillery, obviously. However, you can also force crews out of tanks with a well placed shot or anti-tank grenade (if it disables the turret), then repair it, put in your own crew and turn it loose on the enemy. In case of open-topped vehicles, you don't even need specialized munitions - simply chuck in a standard frag grenade. The series should be called Grand Theft Tanks, to be honest.
* ''VideoGame/EmpireEarth'' has Priest units that convert enemies to their side ...unless those units are near a [[DevelopersForesight university]].
** The sequel adds the caveat that the converted unit is immediately turned into the converter's era-appropriate version if they're at different TechnologyLevels (e.g. a prehistoric priest converting a modern mortar soldier gets an archer, a modern priest converting a spearman gets a machine gunner), with cavalry/tanks being replaced by their highest/lowest tech level equivalent. Even more jarring is the fact that they take on the appearance of the converter's civilization as well, most dramatically seen with the all-black African civilizations and the paler-skinned Far East / Middle East / South American / European civilizations.
* Taking over buildings or vehicles is a very frequent mechanism in ''VideoGame/OriginalWar'' with a few missions centered around it.
* There are several methods for this in ''VideoGame/StarWarsEmpireAtWar'':
** Mara Jade and Emperor Palpatine have a special ability that will [[CharmPerson convert]] nearby (non-hero) enemy units to the their side. However, said units will automatically die off after a short period of time.
** Similarly for the Rebels, Chewbacca can take over nearly any enemy vehicle (including ''AT-AT's''), and R2-D2 can hack into enemy turrets to convert them.
** In skirmish mode, players will occasionally come across capturable buildings which can build units from the non-playable pirate faction.
** This is taken a step further in the ''Forces of Corruption'' expansion, where the new Zann Consortium faction has multiple heroes that can "bribe" enemy units to fight for you, and their corruption mechanics in the campaign and Galactic Conquest can make some enemy units buildable.
** And as if that wasn't enough, there are several [[GameMod mods]] for the game which feature units that can capture enemy starships, and some of them even let you keep the captured units for future battles in Galactic Conquest.