In RealLife, wars are a messy and tiresome affair. Hostilities can escalate for months long before the sides even exchange the first shots. Even the [[BadassArmy best war machine in the world]] will still take its time securing the enemy lands, trench by trench, if not because of fierce resistance on [[LaResistance both sides of the frontlines]], then because marching in too fast will stretch the lines of communications and supply too thin for normal operations.

In fiction, however, the dramatic rules require the invaders to appear larger than life, to establish them as a credible threat unbeatable by normal means. The simplest way to emphasize the superiority of the invader's military might and technology is to establish that they [[CurbStompBattle completed their takeover before the invaded state even knew they were there]]. The survivors will later refer to the invasion as the "[[GreatOffscreenWar One Week War]]", or the like.

{{Alien Invasion}}s often receive this treatment but it is not limited to them; for instance, [[AIIsACrapshoot rogue AIs]] usually take nanoseconds of processing time to peg humans as the enemy and launch a RobotWar. However, it is almost always some [[AppliedPhlebotinum fantastic element]] that allows for this trope to occur and [[EasyLogistics bypass the standard logistical problems]].

A large-scale subtrope of CurbStompBattle and, in many cases, EasyLogistics. A common setup for BackFromTheBrink scenario. HomeByChristmas would be when someone is ''expecting'' this kind of war, only for things to turn out much less than expected. Compare also EasilyConqueredWorld, wherein the defenders fail to offer any resistance to much weaker invaders.

''Note that the title shouldn't be understood literally: to qualify, conquests don't have to take place within a single night; any improbably quick conquest (relative to the size of captured territory) qualifies.''
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!!Examples:

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[[folder: Anime & Manga ]]

* This is pretty how the Kushan Empire invaded the Capital City of Windham in ''{{Berserk}}''. Moments after the King of Midland dies, Emperor Ganishka and his troops come storming in and take over the joint.
* In ''MobileSuitGundamF91'' the Crossbone Vanguards quickly take over the colony within mere hours, as forces of TheFederation were borderline weak to useless in defending the colony.

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[[folder: Comic Books ]]

* MarvelComics has a 2012 CrisisCrossover called "It's Coming" which deals with a BadFuture in which The Phoenix is supposed to come back to Earth and reduce it to an ash-filled wasteland devoid of life. In the future, they call the cataclysmic event "The Six-Second War".

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[[folder: Film ]]

* In ''CanadianBacon'' the Canadian-American war ends before hostilities can even begin when the Americans realize that all their nuclear weapons can be remotely controlled from Toronto. The American President surrenders to the Canadian Prime Minister who is not even aware that anything out of the ordinary is happening.
* ''Film/RedDawn1984'' has the Russians occupying a large swathe of the USA within the space of days.
** The [[Film/RedDawn2012 2012 remake]] does the same, replacing the Russians with the Chine-- sorry, North Koreans.
* The Psychlos of ''Film/BattlefieldEarth'' beat down humanity in about nine minutes. Presumably all the mighty warriors responsible have since left to conquer other galaxies and left the dregs on this backwater; it's the only possible explanation.
** The Psychlos don't fight in the conventional sense. They teleported nerve gas drones all over the world. Presumably, human forces didn't even have a chance to fight.
* ''Film/TheChroniclesOfRiddick'' has Helion Prime taken over by the Necromongers in one night. Then again, we're only shown a single city, but the Necros treat it as if the entire planet is under their control.

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[[folder: Literature ]]

* Creator/RobertAHeinlein's novel ''Literature/SixthColumn'' (AKA ''The Day After Tomorrow''). The [=PanAsians=] use their vortex beams and A-bomb rockets to defeat the United States in less than a day.
* ''Literature/TheMouseThatRoared'': The Micronation of Grand Fenwick declares war on the US with the premise that they will lose and then get repaired, pumping money into the Fenwickian economy. Then they accidentally capture the Q-Bomb and win. This is before anyone in the US even knows the war is going on.
* At the beginning of ''[[Literature/{{Animorphs}} The Ellimist Chronicles]]'', Toomin and his friend are playing a war game. Toomin's side is defeated so quickly he has to watch the replay in slow motion to find out what happened.
* In MichaelMoorcock's "Eternal Champion" story, the Eldren, under their military commander [[spoiler:former human Champion Ekrose]] perform a KillEmAll on every human on Earth within a very short (unspecified) span of time. Justified as the Eldren have ray guns, and the humans have classic middle ages armor, swords, and so forth.
* ''[[Literature/CiaphasCain Cain's Last Stand]]'' makes a very big deal that an invading Chaos force is progressing far faster than it has any right to, and even seems to be growing. They find out that it's because Warmaster Varan has [[spoiler: the ability to instantly brainwash any who hear or see him, including over a public-address system]]. In addition, Necrons have weapons that disintegrate targets and can teleport to just about anywhere they please, resulting in a CurbStompBattle.
* The prequel book of ''Literature/TheTripods'' indicates it only took a few weeks after the Trippies started passing out Caps for the world to end up with more Capped than Uncapped. Some pockets of fighting went on for a while, but it's obvious by the end of the prequel that the Capped are in control.

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[[folder: Live Action TV ]]

* ''Series/BattlestarGalacticaReimagined'' begins with the near-obliteration of the human race in a surprise attack that's over before anyone's realized what's going on.

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[[folder: Video Games ]]

* Between the first incursion in ''VideoGame/HalfLife1'' and the thoroughly subjugated world of ''VideoGame/HalfLife2'' is "The Seven-Hour War".
* In the Strangereal continuity of the ''VideoGame/AceCombat'' series, the [[VideoGame/AceCombatZeroTheBelkanWar Belkan War]] began on March 25, 1995 and would have ended with Belka's victory on April 2, if it were not for [[SpannerInTheWorks the single remaining ace]] (that's you) who delivered his country BackFromTheBrink.
* The Reaper invasion of Earth in ''VideoGame/MassEffect3''. As lampshaded in the intro sequence, it took them ''minutes'' to cut through all the defenses piled up around the human homeworld and land in force. There remains a small planetside resistance but Earth is otherwise firmly under Reaper control for most of the game.
** The Batarian homeworld fell even quicker, as many of their leaders turned out to have been [[MoreThanMindControl indoctrinated]] and disabled the defenses.
** The asari homeworld Thessia also falls fairly quickly once the Reapers themselves get involved; it has a longer resistance to husks, many which die instantly to any directed force attack, because the entire asari population is biotic. Of course, the Reapers are devastating forces of destruction, they're there en masse, and asari culture isn't very military-oriented to begin with; the turian homeworld Palaven, held by a race who consider military service to be a RiteOfPassage and get [[ProudWarriorRaceGuy krogan support]] at the end of the first act, is a comprehensive aversion even though when you first see it most of its major population centres are on fire. Kahje, meanwhile, will be either perfectly safe or instantly doomed depending on your solution to the notoriously buggy Citadel: Hanar Diplomat mission.
* In ''VisualNovel/{{Sunrider}}'', the PACT invasion of Cera took less than one night.

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[[folder: Western Animation ]]

* ''WesternAnimation/ThunderCats2011'': The Lizards have devastated the entire kingdom of the Cats in just one night. Justified as the Cats have medieval level technology, while the Lizards are armed with high tech weapons such as laser guns, bombs, and giant mechs.

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[[folder: Real Life ]]

* In the early stages of WorldWarTwo, Germany conquered the Netherlands and Belgium in a matter of days.
** Then there was Denmark, when the Germans mounted a surprise invasion on the morning of April 9, 1940, which led to Denmark's surrender in about six hours.
* The [[http://en.wikipedia.org/wiki/Conch_republic Conch Republic]] in Florida. In 1982, after the Border Patrol set up a checkpoint at the only road out, Key West declared independence and attacked the United States... by [[FelonyMisdemeanor whopping a man in a Navy uniform over the head with a loaf of Cuban bread]]. One minute later, they surrendered (to the man in the Navy uniform) and [[RefugeInAudacity applied for one billion dollars in foreign aid]].
* There were a couple of real wars with names like these, such as [[http://en.wikipedia.org/wiki/Six_day_war Six-Day War]] where Israel had a major victory over several Arab nations in a course of one incomplete week in 1967, or Russian-Georgian war in South Ossetia in 2008, which pretty much turned into a full-scale Georgian rout after its second day, but is commonly called the [[http://en.wikipedia.org/wiki/Five_Day_War Five-Day War]], because of the cease-fire agreement date.
* There's also the [[http://en.wikipedia.org/wiki/Anglo-Zanzibar_War Anglo-Zanzibar War]], which lasted all of a whopping 40 minutes before the conflict ended. It's the shortest war in history.
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