Easily Thwarted Alien Invasion

"When you aliens are watching Independence Day, I hope what you really take away from it is this: Randy Quaid can kill you. That's not good news, space monsters. Randy Quaid isn't our best human. Here on Earth, we make Randy Quaid wear a helmet when he tries to think. Of Mice and Men was actually a Randy Quaid reality show."
Seanbaby, "5 Movies Aliens Should Watch Before Trying to Invade Earth"

The easiest way to write an Alien Invasion is to make the invaders nigh unstoppable by giving them technology and weapons we can't even comprehend, defend against or overpower. If they were just like a human army, it might as well be a war story; there must be something about the aliens that makes them distinct from any other army.

But the heroes and humanity can't just be dispassionately crushed under a cosmic steamroller, because a Cosmic Horror Story would be a box office dud due to the bleak narrative and Downer Ending. Besides, who would want to read that kind of story?

So what authors do is craft an Easily Thwarted Alien Invasion. To compensate for the aliens' unstoppable power they build in a glaring and common weakness that the heroes and humanity can use to beat back this alien menace once it's identified.

This doesn't just apply to armies, but can be done for individual aliens and non-sentient alien monsters. Maybe their skin is tough enough to stop bullets, or they're telepathic, or they have mind-control powers, or they have some sort of martial society and cannot comprehend "mercy", "surrender" or "peaceful coexistence". Whatever their advantage or power, it's always balanced by a vulnerability to an over the counter product.

And sometimes, that Achilles' Heel is so serious that the humans don't even have to figure it out — the planet takes care of them without any help from us at all. The flora and fauna will make them all die naturally without human intervention, be it from the common cold or water or daffodils. Sometimes, the aliens don't even know it's a weakness (or can't conceive of it as one) until they begin dropping like flies from it.

This can extend to making the cleanup after the invasion a snap. By handing humanity victory on a silver platter and having an epilogue where the characters happily explain how easy it was to destroy the aliens and return to life as if nothing had happened. Grimmer portrayals will give humanity one chance to exploit the weakness after they devastate the planet, making the victory a Bittersweet Ending.

This trope can sometimes be justified if the "alien invasion" is actually only carried out by a few individuals, especially if they're completely ignorant about Earth, as is the case in many old Science Fiction movies.

Compare Rock Beats Laser. See also Weaksauce Weakness and How to Invade an Alien Planet.


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    Anime and Manga 
  • Subverted in Super Dimension Fortress Macross, when just as the main cast finally deduce the aliens' weakness, the Zentradi wipe out Earth anyway.
  • Keroro Gunsou:
    • While mostly the characters are too lazy to pull off an invasion attempt, when they do you can bet it'll fall apart pretty easily.
    • One season finale involved a massive, monolithic alien the size of a city that was defeated when it slipped on a banana peel, which sent it hurtling into the sun.
  • Urusei Yatsura has a few of these. The series started with the Oni deciding to invade Earth, but then deciding to call it off if a randomly chosen earthling could beat Princess Lum in a game of Tag. Naturally, Ataru manages to win (even if he does end up unintentionally proposing to their princess in the process). Other invaders include a bunch in a spaceship that got mistaken for a rugby ball (the battering it took, plus the way Ataru chased the princess in charge after being miniaturised into it scared them off). Also there was the time a shapechanging alien came to Earth and tried brainwashing the locals... unfortunately he disguised himself as Ataru... and his brainwashing technique involved pressing his lips against his victim's.
  • Heroman. The Skrugg are only around for about a whole of 8 or so episodes, and while they totally destroy the US Government, Joey and Heroman still manage to kick their butts to hell and back in a timespan of two or so days. Also subverted near the end of the series, where they're not just back, but even stronger.
  • Played With in Dragon Ball Z. The Saiyan Saga is all about the main cast preparing for an alien invasion from a powerful race that took two of the Earth's best fighters (one who is part of said race) to take down and it was mostly due to luck. The Saiyans are dealt with by a handful of people, but they killed most of the defenders, destroyed a city, and the military in the anime. A couple years later, Frieza and his father come for revenge with a ship filled with soldiers and are killed quickly by Trunks with no casualties. This trope is then completely subverted in the Buu Saga with all the defenders on Earth being overwhelmed by Buu and world is eventually destroyed.

    Comic Books 
  • Toyed with in Blue Beetle, with the Reach, a race of invaders who know they're easily thwarted... so they come on like friendlies and engage some very long-term planning that will give them the planet in a couple of hundred years. When their plans are exposed, Earth's governments (DC Earth being no stranger to alien invasions) immediately demand the Reach's surrender. They get it.
  • In JLA: Year One the ruler of a planet of elemental giants sends seven of his greatest warriors to a certain backwater planet for a grand battle to decide the new leader. The battle never happens; all seven are defeated by local superheroes within minutes of their arrival. The warlord decides that Earthlings are too dangerous to live and orders a full-scale invasion. And is, of course, beaten.
  • Of all the aliens in the Marvel Universe, the easily thwarted award has to go to the shapeshifting Skrulls. Their first appearance in Fantastic Four #2 sees Reed Richards tricking them into thinking Earth is too dangerous to invade by showing them drawings of monsters. In Secret Invasion, which sees the Skrulls throwing hundreds of advanced warships, dozens of overpowered Super Skrulls, and a new technique for completely undetectable shapeshifting, they ultimately lose after a small skirmish in Central Park and The Incredible Hercules leading a team of Divine champions to kill the Skrull's gods. When you have to kill gods to beat the bad guys, it's kind of debatable whether they count as "easily thwarted".
    • Similarly, in an early comic, an alien lands on Earth with the intention of conquering it, but just happens to run into Thor, who promptly defeats him in battle. Thinking Thor is a native of Earth, the alien falsely believes that the entire human race is as powerful as him and he flees.
    • Played for Laughs in another storyline in which an alien invasion is thwarted by three X-men. The ground assault is derailed since the soldiers are introduced to the wonders of beer and gambling, and the entire fleet is wiped out by a drunken Havoc.
  • Played with with the Vespa in Irredeemable. At first, it seems that one lone Badass Normal hero snuck into their ship and forced them all to leave Earth just when things looked grimmest. Turns out he struck a Deal with the Devil with them instead.
  • Subverted in Paperinik New Adventures: at first it seems that the might of the galaxy-spanning Evronian Empire is being held back by Paperinik, AKA Donald Duck's Super Hero alter ego (they were risking their first defeat ever, according to the commander of the invasion force), but as the story progresses it's made clear that, due a combination of rebellions among their subject species and one of their previous successes unleashing the sci-fi equivalent of a Physical Goddess against them, they're overstretched to the point the Humans can beat back a direct assault, and Paperinik is doing nothing more than thwarting their attempts at soften up our defences.

  • In the classic horror movie The Day of the Triffids, the eponymous carnivorous plants are killed off by sea water. Contrast with the original novel in which the invasion isn't thwarted, the survivors instead having to adapt to the Cosy Catastrophe.
  • Independence Day. A fleet of scientifically advanced homicidal aliens has its force field defense taken out by a computer virus uploaded from a Mac, allowing the humans to blow up their base ships by attacking the ship's primary weapons as they fire.
  • The More Than Mind Controlling viral aliens in The Invasion had, in a matter of three or four days, infiltrated most of the Washington population and (going by the Shuttle debris pattern) must have had agents all over the US and the world, painting a scenario where humanity will inevitably fall no matter what it does. But, the heroes discover that some people who had a rare kind of bacterial infection in the brain were resistant to their virus, and in a matter of hours after delivering one such person had created a Magic Antidote which they delivered to everyone infected via dispersing it in the air. The film concludes with a near Reset Button, one character points out that we might never find and cure all infected individuals, but notes that we are in control of the planet because there are still wars.
  • Humorous example: Mars Attacks!! and yodeling.
  • In Signs it turns out plain old water is pretty much a deadly acid to the aliens. Yes, they clearly felt like a challenge invading Earth. Although their weakness is not really that necessary given that this is a race that can be stopped by a pantry door that probably wouldn't have kept a determined human in. Amazingly, they conduct their invasion unarmed save for a natural poison gas gland on their wrist that exhales a small amount of localized gas. And worse still the aliens also forgo armor or clothing of any kind. They're also weaker, slower and clumsier than the average human with apparently no concept of hand-to-hand combat, to the point where one of the main characters beats an alien to death with a baseball bat and it doesn't even try to put up a defence. It's like if humanity invaded an acid-covered world, with frequent acid rain and despite the hostile environment decided to engage the natives naked.
  • Evolution had the aliens thwarted by Head and Shoulders Shampoo's Selenium Sulfide, which they hadn't even tested on an alien organism beforehand.
  • Prince of Space. The chickenmen of Krankor are able to travel half a million miles to invade Earth (even though their fuel capabilities lag far behind ours) where they have their asses handed to them repeatedly by a man who has no superpowers, but can skip reasonably well. Turns out that their weapons have no effect on him.note 
  • Averted in Man of Steel. Superman was more powerful than the other Kryptonians but through combat expertise they were largely able to come close to killing him at a few points, and successfully held off the military. Even Sensory Overload was something that they could manage. Humanity would have been completely terraformed out of existence if weren't for Superman, Lois Lane, Jor-El's digital avatar and brave soldiers working together. Fittingly, almost none of the Kryptonians died at the end of the movie, and were only banished back to the Phantom Zone. By contrast, a lot of humans—soldiers and civilians alike—lost their lives.
  • The French comedy Le Gendarme et les extra-terrestres (The Gendarme and the Extra-Terrestrials) has police sergeant Ludovic Cruchot discover that aliens have landed in Saint-Tropez. They appear to be Mechanical Lifeforms with the ability to take on anyone's appearance and have Mind over Matter abilities. They also easily rust from water, which is how the gendarmes defeat them. The thing is, it's never made explicit that the aliens had hostile intentions. In fact, one of them appears to Cruchot in the form of his Da Chief and offers flowers as a peace gesture. Cruchot's response? Try to kill the alien for... not sure what.
  • In The Thing (1982), it's extremely fortunate that the ship carrying The Thing crashed on an ice desert continent with very little life to assimilate. It's even more fortunate that the few humans available for consumption have access to flamethrowers. The Thing quickly realizes it's at a disadvantage and attempts a Divide and Conquer strategy so it can pick off the camp one by one. Every time it is forced to reveal itself, it only manages to kill one or two people before being quickly immolated or blown up.
  • In Slither, the alien parasite that has been stated to be responsible for multiple planetary genocides is stopped after destroying a small remote town. Sure, people died, but it's nothing compared to every living thing on Earth being destroyed. It's possible none of the previously-conquered planets had explosives.
  • The Chitauri invasion in The Avengers (2012) consisted of what amounts to light infantry and a handful of much hardier Leviathans. Yet Loki and The Other were positively certain they'd be enough to take over the entire planet. While they do have the titular Super Team on the ropes at one point, their lack of tactics past a Zerg Rush and the fact they're susceptible to human sidearms makes a longterm victory unlikely. However, that doesn't even come to pass when a single (mostly accidental) attack on their home dimension reveals they're a Keystone Army and they're instantly killed.
  • Plan 9 from Outer Space has an invasion that involves a zombie apocalypse consisting of three noncontageous zombies

  • Harry Turtledove's short story The Road Not Taken posits that the secret of interstellar travel is an absurdly simple technological concept (so much so that it seems obvious in retrospect, like the wheel), and yet Earth, by sheer happenstance, never stumbles upon it. Later, Earth is invaded by aliens in wooden spaceships armed with cannons and black powder muskets... who are confronted by humans who, having never discovered FTL drives, have instead devoted their research to other scientific pursuits, such as weapons that outclass the invaders' by centuries of development. The story ends with the captive aliens horrified that the humans will be able to discover the secret of hyperdrive from their ship, unleashing the violent, tremendously advanced (compared to other species) humans upon the rest of the galaxy.

    The sequel picks up a thousand years later, when the human race (now stagnant for the same reasons as everyone else) tries to invade a race that still hadn't found the trick, but were now advanced enough that they don't need it to carve out an interstellar empire.
  • In the Worldwar series by Harry Turtledove, the Race, lizardlike alien invaders, intend to avoid this by showing up loaded for the bear. Their probe showed mounted knights on horseback, spear wielding tribesmen, and wooden ships. Thus, they brought automatic rifles, tanks, jet fighters, and nuclear weapons. The time between their probe sending them the information and the invasion force arriving was 800 years, but things don't move on much in that kind of time, at least not for the Race and the other two planets they've conquered. Unfortunately for them, "Tosev 3" is different. The invaders show up in the middle of World War II to find humans not able to match them one for one, but certainly able to compete with them and defeat them, especially when the humans vastly superior numbers and willingness to sacrifice themselves in droves come into play. Then winter rolled around, and the Race realized that, compared to their home planet, Earth is REALLY cold during winter. Especially in Russia. It turned an expected walkover into the aliens having to be content with conquering only parts of the planet that couldn't fight back effectively, or were in the equatorial belt and warm enough for continuous operations.
  • Subverted in When The Tripods Came, the Tripods prequel. The first three Tripods are easily destroyed, and everyone believes this trope. But then The Trippy Show comes along, and...
  • Out of the Dark by David Weber goes along a similar premise to World War except that it takes place in the modern day and the aliens get most of the world's governments to surrender within days by dropping large amounts of rocks. But their ground forces still get Curbstomped by the various Resistance groups that crop up ranging from an alliance between Al-Qaeda and an American Armor Battalion to a couple survivalist families in the Midwest. Up until the aliens rediscover nerve gas, but then Vlad Drakul wakes up and kicks alien ass.
  • Anne McCaffrey loves this trope.
    • In the Freedom series, the preferred host species of the Eosi (body-snatching Evil Overlords) is deathly allergic to a plant that grows in abundance on Botany, the planet the main characters were stranded on. La Résistance manages to sneak boatloads of the plant's pollen into the ventilation system at a suspiciously fortunate gathering of 90% of the Eosi. The surviving Eosi were too few and scattered to retain their grip on their servant races.
    • In the Acorna Series, the Khleevi (Always Chaotic Evil planet despoiling insectoids) are easily cowed by one squadron of battleships fighting back (though they were portrayed as bullies who preferred easy targets). And, after that, the heroes find a plant whose sap acted like purest acid on Khleevi exoskeletons.
    • In the Talents series, the Hivers (a more rapacious version of the Buggers from Ender’s Game) prove to be completely unprepared for human telekinesis. Later, humanity found a pheromone combination that turned the Hivers from Borg-like aggressive conquerors to more docile, agrarian types.
    • In the Dragonriders of Pern books, Thread is a ravenous mycorrhizoid spore that can eat virtually anything carbon-based and burrow into the earth. But water (even a good soaking thunderstorm) kills it, as does fire and cold. In one book, the Pernese don't realize that Threadfall has started because the first few falls are over the northern area of the continent during winter. Also grubs, but those were genetically engineered.

      If it seems improbable that Thread could ever live on any planet with anything worth eating, that's because it is. It's a deep-space organism which only falls on Pern due to a very unfortunate accident. Once Thread falls, it's doomed — but it can still do a hell of a lot of damage before it dies.
  • Battlefield Earth had a very specific set of weakness that made their occupation of Earth (not the invasion itself) easily thwarted... as well as the annihilation of their race. The gas the Psychlo breathe combusts in proximity to radioactive materials, but no alien race fighting them was ever in a position to best them militarily and get a nuke near them (only a nuclear device could combust an atmosphere's worth of gas). As it turns out their teleporter net connected all of their planetary holdings everywhere, so if a nuclear device were smuggled on their homeworld and the detonation was timed to coincide with these teleporters activating it would incinerate every Psychlo in the universe. Luckily for them, no aliens could get near their conquered planets, and none had the intimate knowledge of Psychlo technology and organization to pull it off... until one of them gave a human the smarts to figure it out.
    • In a straighter application of this trope, Johny is inspired not to think of the Psychlos as invincible when Terl shows him the site of greatest military resistance... the US Air Force Academy. The cadets had figured out the Psychlos were using nerve gas and wore gas masks, and proceeded to put up quite a fight until overwhelmed by numbers.
    • Granted, "quite a fight" is sort of a misnomer. They conquered Earth (according to the movie) in three minutes. So this "quite a fight" must have been all of two minutes long. Not to mention the fact they annihilated our military in three minutes implies they had hella fast deployment capabilities... which, if you think about it, makes sense as they could probably use teleporters to just beam down a few tens of millions of dudes.
    • The Psychlos actually put a radiation detector on their transporter with it programmed to not transport anything radioactive. When the nukes were sent in the teleporter detected radioactive material and activated a quarantine shield; the issue was the humans kept teleporting in nukes, and the planet had been so thoroughly mined for resources, with so many holes left over from mining, that the blasts reached the core of the planet and (somehow) made the core react explosively, destroying the entire planet.
    • In the proper application of this trope, when the humans see the airplanes (Which had been previously ineffective), they are able to easily learn how to use them and fight the Psychlos successfully. Despite having learned how to use these things in a matter of weeks and them not having worked the last time.
  • In Arthur C. Clarke's Space Odyssey series, the godlike aliens who blow up planets and mess with humanity's evolution from apes are found to be vulnerable to computer viruses... the code for which are buried in a mountain on the moon.
    • However, the supercomputer that the virus is uploaded to helped humanity upload it.
    • Also, it is explicitly explained that the viruses in question are not just your regular run of the mill viruses - they exploit the laws of mathematics such that ANY computing system that uses numbers is vulnerable, no matter how advanced, and NO countermeasures of ANY kind are possible.
      • The supervirus were described as working by tricking the target computer into attempting a calculation that was impossible to complete meaning that they could in theory work against any calculating system no matter how advanced. However they presumably can be stopped at the point of infection by a good firewall like any other virus, which was probably how they were in the end contained and put into the lunar vault with all the other weapons of mass destruction. The target was the monolith, which was just a single machine, a single mostly autonomous tool of the aliens, not the alien civilization itself, and in fact had been corrupted and damaged after millions of years of wear and tear which may have made it more vulnerable. But even then humanity would have had no hope in hell of successfully infecting it at all without Halman's help. The conclusion of the last novel also left it ambiguous as to whether the supervirus actually worked or not, or was even necessary. (The monolith may not have been planning to destroy the solar system at all and humanity was just being overly paranoid. The supervirus might have failed completely and the monolith left the solar system because that was what it was intending to/instructed to do all along. Alternately the monolith was destroyed by the supervirus, but fights it off long enough to send a You Suck message to humanity, and call for reinforcements, which presumably would arrive sometime around 5001.)
  • Older than Television: The War of the Worlds did this with bacteria. In fact, it's pretty much the Trope Maker and Trope Codifier for the "The planet takes care of the invaders itself" version of this trope.
    • The novel implies that the Martians were severe germaphobes who rid their native habitat of all microbial life, thus blessing themselves with major suck right before the invasion of Earth.
    • In Wells' defense, he was writing before the discovery of antibiotics. Prior to WWII, far more soldiers of any invasion died of contagious diseases than battlefield injuries, and even in peacetime the British Empire lost scads of troops to malaria, yellow fever, and other tropical ailments in its overseas possessions. So the Martian imperialists weren't suffering from anything that Europe's own imperialists hadn't. (Wells took a dim view of imperialistic expansion.)
    • Subverted in The League of Extraordinary Gentlemen: Book II, where the bacteria which kill the Martians are actually products of Dr. Moreau's genetic engineering and hybridization.
  • The Hitchhiker's Guide to the Galaxy
    "For thousands of years the mighty starships tore across the empty wastes of space and finally dived screaming on to the planet Earth - where, due to a terrible miscalculation of scale, the entire battle fleet was accidentally swallowed by a small dog."
  • Robin Cook's Invasion had the Replicant Snatching aliens thwarted by the release of a rhinovirus, AKA the common cold.
  • Keith Laumer wrote a hilarious short story in which aliens invade a dying civilization — only to discover that the locals were in fact immortals whose metabolisms shut down if they didn't get enough of a certain gas in their air. Guess what the invaders exhaled. And the locals who were still up and about were the weakest of their species; the invasion revived all of their brawny Badasses.
  • The invasion of the Gorg in The True Meaning of Smekday. For some reason, the Gorg try to kill every single cat on planet Earth. As it turns out, the Gorg are allergic to cats due to cloning themselves so much.
  • The Body Snatchers, the short story upon which the film versions were written, had the aliens simply give up when the figure out they can't tolerate human resistance. The films tend to end on a darker note...
  • Rather than a single cataclysmic event, Christopher Anvil's short story The Gentle Earth covers a long campaign in which the invaders are slowly worn down, but they're defeated in such a thorough and humiliating fashion that it goes under this trope anyway. Their errors and catastrophes include but are not limited to failing to prepare appropriately for Earth's much colder winters, dismissing tornadoes as a legend (having landed in Tornado Alley), and drastically underestimating Russia's missile supply.
  • In Stephen Baxter's novel Space has the solar system invaded for use as an stellar fuel depot by the Crackers, which will result in the explosion of the sun. Having battled through the friendly Gaijin fleet, they are utterly destroyed by Nemoto's secretly modified and transplanted Moon Flowers, which use the top layer of Mercury's soil as cosmic buckshot.
  • Averted in Greg Bear's Forge of God where humanity is totally screwed even before we realize we're under attack, have absolutely no way of even inconveniencing the invaders even a little bit even after we find out, and the total destruction of the Earth is a foregone conclusion from essentially the first page. In the end we nuke a few decoys but never even see the aliens or their principle weapons. A few survivors are rescued at the last moment by another perhaps more benevolent alien race, but at least according to some interpretations of the sequel, it was only to be used as pawns and cannon fodder in a wider galactic war.
  • Arrivals from the Dark: In Mikhail Akhmanov's Invasion, the super-powerful alien starship wipes out a large chunk of Earth's fleet and shrugs off a nuclear Macross Missile Massacre without a scratch. In a Deus ex Machina fashion, a different alien teleports onboard and gives the hero a device that destroys the ship's brain, shutting down all systems. In a brutal subersion of No Endor Holocaust, many major cities get hit with smaller falling alien ships full of antimatter, with the casualty count in the tens of millions, not to mention all the material damage. Earth recovers remarkably quickly in the sequel, though.
  • Lampshaded by the character of Zellaby in John Wyndham's The Midwich Cuckoos (1957), where he brings up a few examples of this trope common in British and American science fiction at the time in a strategy discussion. He then concludes the alien invasion they face is a war like any other, and takes the appropriate measures.
  • The Sirens of Titan by Kurt Vonnegut features a Martian attack on Earth. The Martians originate from human colonists and appear to be extremely well-prepared and equipped, but several mistakes in their plans make it extremely easy for Earth to repel the invasion.
  • A novel titled Invader (can't remember the author) had humanity's astronomers spot the massive energy release as the invasion fleet slowed from near-lightspeed, so the world's governments funded the construction of a massive gamma-ray emitter. One carefully-aimed shot killed every living thing in the fleet, and the now-dead ships just drifted past Earth back into the void.
  • The High Crusade: Invaders landing in England in AD 1345 can only defend themselves against energy weapons, leaving themselves helpless against swords and arrows.
  • Animorphs: The Helmacrons are a microscopic species with egos the size of planets. Their one invasion force is a single ship the size of a plastic toy, and they still think they can win. To quote Marco, who snaps after constant exposure to their bravado:
    "You couldn't hope to go mano-a-mano with a maggot and win. And that's sad, because maggots don't even have manos."
  • In the backstory of Charlie and the Great Glass Elevator, the Vermicious Knids have tried to invade and conquer Earth the way they did the Venus, the Moon, and Mars, but Earth's atmosphere is too much for them — what look to humans like shooting stars are actually Vermicious Knids burning up when they try to pass through. In the novel's present, they invade Space Hotel USA and manage to eat some of its crew, but the rest are rescued by Willy Wonka and company using the titular elevator to tow their ship to safety. When the aliens attempt to drag the humans to their home planet, Mr. Wonka instead steers the elevator and ship back into Earth's atmosphere, finishing the monsters off.
  • The aversion is discussed in Vladimir Vasilyev's Wolfish Nature by Rasmus. According to him, Earth is woefully unprepared for an invasion by any alien power capable of interstellar travel, in large part because the Bio-Correction turned all dog-humans into pussies incapable of killing without going insane. Really, Earth's only saving grace is the lack of anything even remotely useful to any aliens (e.g. resources, strategic position, technology). The last time they found something useful was a few hundred Medieval warriors to use as shock troops in their interstellar wars. Rasmus is their leader.
  • Ultramarine series of Warhammer 40,000 features a Tyranid invasion on Tarsis Ultra. It was a tendril that made up half of supposedly unstoppable Hive Fleet Leviathan that was annihilated by 2 companies of Space Marines, 2 Imperial Guard regiments and rather small and underwhelming Imperial Navy battlegroup. note  The battle was won when Ventris poisoned the Hive queen, but still. Unfortunately, there are so many similar victories in novels and codices that it makes fans question: if just so few IG regiments and Astartes companies can thwart galaxy-ending threat, why hasn't Imperium that has millions regiments and thousands companies of Astartes won already?

    Live-Action TV 
  • Lost in Space episode "Invaders From The Fifth Dimension" features Will Robinson abducted by a group of aliens who are repulsed by the sight of tears due to being unable to understand emotions, and eventually let him go as a result.
  • The episode "Politics" of Stargate SG-1 is about a Senator who believes that the Goa'uld are this, thus wants to cut SG-1's funding. He's not entirely wrong but underestimates the Goa'uld considerably since SG-1 keeps coming back alive. Destroying the Goa'uld by uploading a computer virus to their ship is sarcastically mentioned.
  • The Outer Limits (1963) episode "Specimen: Unknown" had alien plants that release a deadly gas and spread like wildfire. A spaceship carrying them crashes on Earth and it looks like the human race is doomed. Worse yet, a thunderstorm is brewing overhead, and the plants will spread even faster when they get some rain, right? Wrong. The rain causes them to shrivel up and die, and the world is saved. Think of it as the opposite of a Cruel Twist Ending.
  • Star Trek: The Original Series episode "Day of the Dove". An alien powerful enough to destroy a Klingon battlecruiser, transmute matter and control the minds of hundreds of beings simultaneously takes control of the Enterprise. How do the humans and Klingons get rid of it? By laughing at it. Seriously.
  • Most alien invasions in Power Rangers. Almost universally taken out by "teenagers with attitude". Also, supersuits and giant robots.
    • And not much in the way of attitude, when you get down to brass tacks. Nonetheless, five teens restricted to a single city with no military skill or training whatsoever fend off entire armies that know where they live, who they are, and what they like to do in their free time.
  • Doctor Who loves this trope, with dozens of aliens invasions ranging from single vessels to vast fleets (The World Is Always Doomed, after all) being Easily Thwarted by a single man with unusual dress sense. The spin-off series The Sarah Jane Adventures plays it even more straight than its source material.
    • This generally reaches its extreme whenever the Doctor fends of Dalek fleets. For reference, Daleks are the scourge of the universe, with precious few civilizations being able to stand against even small amounts of them.
      • A major criticism of Russell T. Davies writing for the Series finales was that they always seemed to be solved by a Deus ex Machina. In "Journey's End" a Dalek plan to destroy entire Universes is foiled just because Donna touched a few buttons that no Daleks were guarding.
  • The Science Fiction Sketch of Monty Python's Flying Circus, in which blancmanges from Andromeda seek to win Wimbledon by turning everyone in the world into a Scotsman. They were thwarted when two people ran out onto the tennis court and ate the blancmanges. It would have been more easily thwarted, but the camera rudely cut away early in their first appearance.
  • This trope is referenced in Farscape when the crew of Moya ends up on Earth.
    D'Argo: (gently) I've seen lots of your movies. And in every film - the aliens are always evil and Earth always is victorious.
    Bobby: You mean we have to learn there are good aliens?
    D'Argo: (long pause) No - I mean you have to learn you won't always win.
    Both John and Aeryn also note in the episode that Earth's defenses would be woefully ineffective if any alien race decided to attack.
    • An attempt to invade Earth happens in the series finale (prior to the wrap-up mini-series), when the Scarrans send a single warship to conquer Earth. John ends up destroying it in flight, but is forced to collapse the wormhole to do it.
  • Referenced in the Mystery Science Theater 3000 episode Prince of Space. After the villain, Krankor, announces his plans to conquer the Earth, we cut to newspapers flying off the presses and the 'bots imagine the headline:
    Crow: "Krankor: Nothing to Worry About!"
  • A Saturday Night Live sketch from the '80s ("Target: Earth") featured an invasion by a race that has a spaceship... but in every other way appears to be far less advanced than Earth.
    1st Alien: So, what is your answer? Do you agree to come quietly and be our slaves or do you face the awesome power of our muskets?
  • The Anterians from the Suite Life on Deck episode "Starship Tipton". The ant part of their name probably should have been a tip off.
  • America's Funniest People host Dave Coulier requested viewers to send in videos depicting an alien invasion. Most of them were this. The first showed an alien who details his entire plan, only to be flattened by a car tire bigger than he is.

    Video Games 
  • Subverted in City of Heroes- the extra-dimensional Rikti invaders turned out to be vulnerable to magic, so they targeted magic users as soon as they found out. Their invasion still caused massive devastation, though not quite to After the End levels, and decimated the Superhero population.
    • And then they started learning how to use magic themselves.
  • Averted entirely in Universe at War - The tutorial mission is the only time you play the humans and its Unwinnable; Earth has to be rescued by other aliens.
  • In the original X-Com, the aliens' weakness is logistics. They simply don't have enough forces available at the beginning of the game to launch more than a couple of small missions a month (though their forces build up more and more later), requiring them to operate in secret through infiltration and subversion of national governments, showing the world that X-Com is too weak to defeat them and attacking and destroying X-Com bases instead of open warfare. Meanwhile, even one crashed alien craft allows for humans to import their phlebotinum, and enough research allows them to take the fight to the alien base on Mars.
    • The Remake is an aversion. Your teams note that if the aliens really want to invade us they could do so easily and must have other plans they do.
    • Xenonauts has its first research consisting of explaining "Why we haven't already lost."
      • The Aliens are invading a planet that is nothing like the ones belonging to any of the constituent alien species, Higher oxygen levels, thicker atmosphere, ETC, ETC.
      • The Alien ships need to be refitted for atmospheric combat, which is logistically intensive, and time consuming, forcing them to rely on small scout craft for the early phases of the invasion.
      • Ultimately, this gives humans time to research, and reverse engineer their technologies, to hopefully stop the alien invasion before it gets intense enough to actually become a full scale invasion, which is less then a year.
  • The Rhombulans in Elite Beat Agents are so vulnerable to music that rhythmically beat garbage can lids is enough to knock out their soldiers. The easily-thwarted part happens when you remember what genre this game belongs in, at least from a story point-of-view.
  • Guild Wars 2's main threats, the Elder Dragons, are described as the most powerful things ever... and yet the Vigil alone is shown to have enough resources to wage war against them on as much as three fronts. And the only thing keeping them from actually defeating the dragons is, apparently, their childish unwillingness to work with the spy and the scientist orders. As soon as that happens, all it takes for one dragon to die are a few shots from a bunch of airship cannons.
  • The Half-Life series averts this. The scientists in Half-Life come up with two plans that they hope will Easily Thwart the invading Xenians, but the first is countered by the invaders, and the successful execution of the second plan actually has the opposite effect, and causes millions upon millions of Xen creatures to be teleported all over Earth. The best part? All of this interdimensional activity attracts the interest of a nigh-unstoppable alien empire known as the Combine, who then conquer Earth in an invasion known as the Seven Hour War.
  • The Shroobs in Mario & Luigi: Partners in Time. Right at the very end of the game, baby Luigi's crying on a Shroob Mushroom reveals that the Shroob materials dissolve when exposed to baby tears. The present-time E. Gadd creates an immeasurable amount of water with the same composition as baby tears in response to this. He then pumps it through the time-holes, saturating the past Mushroom Kingdom in baby tears, completely removing any traces of the Shroobs from the Mushroom Kingdom. However, it seems Bowser had Shroob-napped a few survivors and put them in the deep freeze, to be battled in the next game of the series
  • In Earthbound Zero a troupe of three small children (albeit with Psychic Powers) defeats an all-powerful alien by singing.
    • What about the sequel Earthbound where the said alien is defeated by prayer?
    • In both cases, it's more of a sort of softcore Mind Rape performed on Giygas than a Weaksauce Weakness, due to the circumstances.
    • Regardless of the tactics used to defeat Giygas himself, a group of 3 or 4 children basically are capable of fighting off everything Giygas can send at them in a more traditional sense.
  • Averted in the second Dawn of War 2 expansion. In the previous games, the heroes kill the alien Hive Tyrant, destroy their fleet, kill the ork warboss and even take out both the Grater Daemon and the Chaos Lord that tried to free it, so everything is okay, right? WRONG. Ten years later the war rages on with no end in sight and the situation is so grim that the Empire decides to just nuke the entire sub-sector. This is, naturally, par for course in Warhammer 40,000.
  • The premise for the Dawn of Victory mod for Sins of a Solar Empire is loosely based on the Worldwar series by Harry Turtledove (see Literature). The Scinfaxi (not their real name) are a vast interstellar empire, who set their sights on Earth. Same deal, their invasion force arrives centuries after the initial probe, and they land in the middle of WW2. However, their tech is more akin to the aliens from The War of the Worlds. Despite being shocked at humanity's rapid technological progress (Scinfaxi are conservatives when in comes to progress), they manage to conquer most of the world before the Russians manage to steal one of their nukes and blow it up. The Germans and the US follow suit, scaring the aliens into retreating to the southern hemisphere. A century later, humans abandon Earth and nuke the hell out of it, to kill any Earthbound Scinfaxi. Thus begins a war between the aliens, Soviets, Germans, and Americans... In SPACE!
  • Subverted in Sword of the Stars when the Hivers first struck humanity, they soon respond by launching hundreds of nuclear missiles, forcing the Hivers to turn tail.
    • Of course, even that was a tiny colonization fleet of one clan, and it took most of the stockpiled missiles to do it.
  • The Qularr invasion in Champions Online features as the tutorial. They aren't wiped out, but it seems most of their fleet attacks a single city and are driven off when their mothership is brought down. They are generally kicked around by all the other heroic and villainous groups; one open mission is called Nadir Of The Invaders.
  • Averted big time in StarCraft; whenever the Zerg invade a planet, it's usually incredibly hard, if not downright impossible, to stop them. Even when the Protoss manage to kill the Overmind by the end of the original game, the extension reveals that it still didn't put an end to the invasion, and the last protoss survivors are forced to leave to save their skins. The only time they managed to end a Zerg invasion in a relatively short time was in the Brood War Protoss campaign, and only thanks to the combination of three powerful MacGuffins.
  • A possibility in the Expansion Pack to Sid Meier’s Alpha Centauri. The two Progenitor factions have powerful battle fleets waiting for a signal from their respective scoutships. However, if you defeat the aliens, then their fleets never show up, since they simply assume that the scoutship perished without discovering the location of Manifold Six (their name for Planet). Additionally, while the aliens are much more advanced, their scoutships destroy one another, and the survivors land in Escape Pods and must rediscover lost technology, putting them on par with the humans.
  • Seemingly played straight in Command & Conquer 3: Tiberium Wars: GDI manages to shut down the Scrin invasion of Earth after a lot of effort and massive destruction across the globe, and while being hampered by the Brotherhood of Nod which (except for a few token efforts) isn't even bothering to fight against the aliens and is actually prioritizing GDI as a target over the Scrin. Then it's a Subverted Trope when you play as the Scrin campaign and you find out the fleet wasn't an Alien Invasion, it was a mining operation with a small security detail. For most of their time on Earth, the Scrin forces were running an Indy Ploy barely hanging on with lots of Improvised Weapons and uncaring leadership that were willing to let the entire force get wiped out.
  • The Zuvorg Alliance in Super Robot Wars Original Generation, particularly the Guests, though this is mainly due to getting the short end of the Sorting Algorithm Of Villainy. While the Inspectors at least had some time as the main threat of OG 2 (before getting hijacked by the Shadow Mirror and the Einst), in 2nd OG the Guests aren't even able to make landfall on Earth ( thanks to Mekibos providing intell to the Federation) and the threat they pose is quickly eclipsed by the Ruina, Youkijin and ultimately Euzeth Gozzo.
  • In From The Depths, the Scarlet Dawn faction is the leftovers of a failed alien invasion that suffered setback after setback. After having been on ice for centuries while in-flight to the planet Neter, the aliens were extremely frail upon awakening. When they set down a pair of Von Neumann factories to the surface, the machines malfunctioned and lost their shackles, allying themselves to the planet's governing body for protection. And finally, upon landing the planet's extremely violent shifts in temperature, weather, and light allowed their laser-spamming high-altitude fighters to beaten back by the government using little more than armor-piercing cannons and missiles.


    Western Animation 
  • Parodied in Futurama's version of The Twilight Zone, The Scary Door.
    "In the end, the aliens were defeated not by guns or bombs, but by that humblest of Nature's creatures... the Tyrannosaurus rex."
    • Another humorous example example, this time from a B-Movie on a planet of killer robots:
    "The human was impervious to our most powerful magnetic fields, yet in the end he succumbed to a harmless sharpened stick!"
    • Fry repelling the Brain invasion by writing a story full of plot holes and spelling errors.
    • The Omicronian invasion may count too, as the whole point of it was to see a thousand-year-old TV show that they had missed. The Planet Express crew reenact the episode for them, and they all go home.
  • The Simpsons
    • The childless child-hating adults, who had disposable income and free-time on their side, "had no protection against God's lowliest creatures... children." Or to be more precise, 'kid germs' to which they had no natural resistance.
    • In a Halloween special, after humans have destroyed all known weapons, an alien invasion consisting only of Kang and Kodos alone, are able to Take Over the World, wielding only a slingshot and a bat. Eventually the two of them are overthrown and chase away from Earth by a rebellion, consisting only of Moe wielding a more advanced weapon than than Kang and Kodos can conceive of... a board with a nail in it.
    • Another attempt was done when Kodos creates a portal which sends an army of aliens to Earth; it was thwarted by the U.S. Army which easily slaughters all the aliens.
    • In another episode they win by using our stupidity against us. They kidnap and impersonate Bill Clinton and Robert Dole just before the 1996 election. When they are discovered and unmasked by Homer (Who has also accidentally killed the originals trying to save them) they tell humanity that it doesn't matter since it's a two party system, we have to vote for one or the other. (Causing a frustrated Ross Perot in the assembled crowd to tear up his hat). Sure enough, come inauguration day, humanity is enslaved and being forced to build weapons to conquer other planets.
  • In one episode of Care Bears: Adventures in Care-a-Lot, Care-a-Lot is invaded by Gobblebugs, tiny bugs that eat any and all plants, except ones that are yellow. Once the Care Bears realize this, they turn all the remaining plants yellow, and the bugs lose interest and leave.
  • Invader Zim: Not all the Irkens are idiots. Most of them (Especially Invaders) are actually pretty competent. It's just that the story is about Zim. An invader who is so stupid that they sent him into an uncharted area of space to find a planet they made up just so that he would die slowly and horribly due to starvation. They didn't anticipate Zim actually finding the planet.
    • This trope is also parodied in the episode "Germs", where an Easily Thwarted Alien Invasion (by germs) in a bad sci-fi movie makes Zim paranoid about falling into the same pit-trap, and Hilarity Ensues. the Vortians, who were Invaded and conquered by the Irkens. For example, we find out they built and designed the Massive.
  • Agent Bishop faked up one of these to get extra funding for his organisation in the 2003 Teenage Mutant Ninja Turtles series.
  • Aqua Teen Hunger Force gives us the Moonenites, the Plutonians, the Jupiterians, Travis of the Cosmos, and the Frat Aliens.
  • In the Grand Finale of Kim Possible, two aliens and their robot army invade the world "in the time it takes to order a pizza", but only hold on to it for a few hours before being defeated.
  • Not a direct example, but in one episode of the original Transformers cartoon, the Decepticons ceased their attack on the Autobot base because the chaos caused activated its fire-repellent systems... which was made up of fire-retardant foam being sprayed from the ceiling. According to Megatron, if they stayed and continued the attack, the foam would permanently damage their internal circuitry and they would shut-down for good. These are highly advanced Mechanical Life Forms who have been shown surviving being frozen in ice for centuries and being submerged in the deepest areas of the sea and yet apparently the one thing most damaging to them could potentially be found in fire extinguishers. Imagine how easy it would be to get the Decepticons off planet if they just used those?
    • Remember, aim at the base and sweep.
  • In The Powerpuff Girls episode "Beat Your Greens", Earth is invaded by a race of broccoli aliens after all of the adults are brainwashed by eating modified broccoli. Naturally, the children escape this fate and fight back, by literally eating the invading aliens. Naturally, the aliens (and probably some viewers), were absolutely horrified by this.
  • Although the invasion is never shown to have actually happened, in Lilo & Stitch Earth avoids invasion by being the natural habitat of a highly endangered species... mosquitoes. What's more, the decision was apparently based on the testimony of the Earth-native who tricked them, with not even a basic survey done to see if it was true.
    • There was a little bit of implied help from the seemingly Obstructive Bureaucrat, who in a twist of that trope was helping the good guys for once. At the very least, when they get (back) to Earth, she recognizes the secret agent that masterminded the whole shenanigans to save the world in the first place when they showed up the first times, and seems to be on relatively friendly terms.
  • In Big Guy and Rusty the Boy Robot, the alien Squillacci are the ones who draw Crop Circles and experiment on cattle. Their repeated invasion attempts are stopped only by a guy in a Humongous Mecha and an android the size and mentality of a child.
  • In Journey to Saturn, the alien invasion is thwarted by having the heroes throw and shoot beer at them. It probably wasn't a good idea to invade Denmark.
  • In the Birdman episode "Skon of Space", Skon, the advance scout for an alien invasion, attacks Birdman. Birdman defeats him and sends him home with the warning that everyone on Earth has powers like him, so any invasion would be futile. Birdman calls Falcon 7 and warns him to prepare for an invasion just in case Skon's superiors are not as gullible as him.
  • Usually justified to an extent in the original Ben 10 series, where most invasions are stopped by Ben before they could actually reach a large scale (such as the Great One in "The Big Tick," or the Mycelium in "Camp Fear"). Same for Vilgax, whose army is mostly composed of Mecha-Mooks, meaning they will stop working once their leader is gone.
    • Averted in Ben 10: Alien Force with the Highbreeds, whose invasion turns out to be unstoppable in the finale when the protagonists attempt to thwart it by force. The only way Ben is able to stop the invasion is by finding out the reason behind the invasion and help them in a way so they wouldn't need to invade/destroy the universe anymore. Whether this count as easily thwarted or not is debatable.
    • The Incursean invasion of Ben 10: Omniverse is similarly unstoppable by force. It only ended in negotiation after the current leader was abandoned by his treacherous daughter.