Alien Kudzu

At least it prevents soil erosion.

"Next day, the dawn was a brilliant fiery red, and I wandered through the weird and lurid landscape of another planet, for the vegetation that gives Mars its red appearance had taken root on Earth. As man had succumbed to the Martians, so our land now succumbed to the red weed. Wherever there was a stream, the red weed clung and grew with frightening voraciousness, its clawlike fronds choking the movement of the water. And then it began to creep like a slimy red animal across the land, covering field, and ditch, and tree, and hedgerow, with living scarlet feelers. Crawling. Crawling."

— The Journalist, Jeff Wayne's Musical Version of The War of the Worlds

One of the possible side effects of an Alien Invasion.

In essence, Alien Kudzu is a plant-like, fungus-like, or otherwise predominantly sessile alien lifeform that infests a planet's environment and begins reproducing itself rapidly. It is almost always harmful to the local habitat, whether directly (such as giving off toxic gases) or simply by outcompeting and choking out the local vegetation. It is also usually very difficult to kill, making the act of reclaiming these infestations take up great deals of time and resources (if not outright impossible).

The aliens may release it deliberately as part of their invasion in order to Terraform the Earth into a planet more suited to their own environment, or it may be just the result of the alien plants naturally being able to outproduce the local competition.

Alien Kudzu can sometimes be used for a Meat Moss effect as a sort of visual shorthand to show that things are really, really bad.

Note that neither the plant nor the invaders need to actually come from another planet; "alien" in its original sense simply refers to something foreign and/or not native. (Indeed, in Real Life this is common enough that we have a word for it — invasive species — and the kudzu plant is one of the most notorious examples, as any Southerner can rightly attest.) They usually are, though, especially in Science Fiction settings.

Subtrope of Introduced Species Calamity. Compare Explosive Breeder and Fantastic Vermin, which are similar concepts applied to animals, and Botanical Abomination. Named after the same plant as Kudzu Plot, but the two tropes are unrelated. It's also not to be confused with the Newspaper Comic of the same name. For plant overgrows that occur in buildings due to prolonged periods of abandonment, see Reclaimed by Nature.

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Examples:

Anime and Manga

• Cardcaptor Sakura: In one episode, the Wood card causes vines, bushes and branches to overgrow and cover the whole Kinomoto house.
• The Radam trees in Tekkaman Blade are basically this. They grow from the huge insectoid Radam Beasts who burrow into the earth and function as seeds. These trees slowly terraform the earth by emitting gasses into the atmosphere. Their true purpose happens when they bloom, which is to capture humans into their pods and forcibly change them into Tekkamen, brainwashing them in the process to become loyal to the Radam.

Comic Books

• The Doctor Who (Titan) comics described a species known as The Planting, which infests a planet and eventually replaces its entire biopshere.
• The League of Extraordinary Gentlemen Volume 2 deals will Wells' Martian invasion (see Literature below), and so features the red weed. In League's case it is introduced to choke off the Thames river, and so stop the movements of Captain Nemo's Nautilus, the only weapon that was having much success at all against their tripods.
• Wonder Woman Vol 1: Rykorn is a rather problematic quickly growing giant alien plant, it is not only difficult to kill it can grow fast enough to fill the entire Bar-L ranch overnight and within twenty-four hours each stalk's husk births a fully grown Rykornian warrior. Luckily Rykornians themselves are rather small.

Fan Fiction

• In Aeon Entelechy Evangelion Leng is a mythical plateau from the Lovecraftian Another Dimension slowly establishing its hold in our reality, starting with its ecology spreading throughout China and most of south-east Asia.

Film — Animated

• In Disney's Sleeping Beauty, Maleficent causes a forest of thorns to spring up instantly around Stephan's castle in an attempt to kill Prince Philip. It doesn't work because his magic sword is able to cut through the thorns.

Film — Live-Action

• In a segment of the 1982 film Creepshow entitled "The Lonesome Death of Jordy Verril", the title character (played by Stephen King, who wrote the script) discovers a newly fallen metorite. After he is contaminated with the oozing interior "meteor shit!" while trying to retrieve the object, he starts to sprout a plant-like fungus which quickly spreads to much of his body. The substance also causes him to itch unbearably and even after being warned by the ghost of his father not to take a bath, he finally can no longer resist and sinks into the filthy tub. The next morning we see that the water has accelerated the growth of the fungus/alien kudzu and it now covers Jordy, farmhouse and surrounding land completely. Jordy ends his horrible ordeal with a shotgun. The segment ends with a radio weather forcast calling for extended heavy rains.
• Dreamcatcher features a red fungus that spreads like a rash but also grows on the scenery.
• In Guardians of the Galaxy Vol. 2 Ego attempts to turn multiple planets into extensions of himself by planting seedlings on them that would later terraform the planet.
• Invasion of the Body Snatchers embodies this trope. That, and assimilation.
• Jumanji: At one point, after Jude throws the dice and reach a certain tile in the board, the table warns about ivies that not only can shoot poisonous darts, but also turn a whole mansion (the Parish one, in this case) into a deep jungle. The vines eventually extend beyong that residence, swallowing a police car.
• In Super Mario Bros. (1993), the former king of Dinohattan has been de-evolved into a fungus, which got his revenge by taking over the whole city. It helps the protagonists in many ways, such as breaking their falls or providing them items.
  Great, a building with athlete's foot!
• War of the Worlds (2005) shows the Martian tripods seeding the red vines across the landscape (apparently created by converting human biomass into a fine red mist and possibly contributing to the Martians' inevitable defeat by exposing themselves directly to the microbes inside human beings).

Literature

• In a short novel by Brian Aldiss, a couple of an alien race named as the Charioteers soak a rural English farm with an equally alien enzyme, which massively increases production of everything the farm produces: milk, produce and meat, at the cost of making it completely inedible for humans... but perfect for the Charioteers' needs. To make it worse, humans are not exempt from the transformation. A couple of named characters are transformed into aberrations by exposure and the narrator's Love Interest barely survives.
• Aurora Cycle: One of the many pleasant attributes of the Botanical Abomination known as the Ra'haam. When Squad 312 gets to Octavia III, they find that all of the planet's former native fauna is gone, replaced by the Ra'haam. It wants to do this to every world it can spread to.
• The Bongleweed by Helen Cresswell, a children's book about an incredibly fast-growing escapee from a botanical garden, that overruns the countryside during a heatwave. It's defeated when the semi-tropical heatwave (conditions it thrived in) ends.
• The Croach in the Codex Alera. It quickly spreads to cover all territory that the Vord overrun, coating the ground, trees and buildings alike in a thick layer of green, glossy wax. Air pockets within the surface recreate the ideal Vord atmosphere, and any natural life that gets caught in the Croach is gradually broken down into nutrients for the Vord creatures to sustain their biomass. There are specialized creatures that spread it, much like the red plants in The War of the Worlds (1898).
• H. P. Lovecraft's The Colour Out of Space in which a meteorite lands in a small, backwards New England farm. The meteorite contains an alien colour which infects the land and water around the farm. Ammi Pirece, the narrator telling the story to a guy from a land development agency, states that the area of infection/contamination is growing slowly, year by year...
• The Triffids from The Day of the Triffids may count. Depending on the character, interpretation and adaptation they are either an invasive alien species or genetically-modified organisms. The truth is never known for sure.
• The grey mould in Expedition Venus by Hugh Walters. In this case it's not associated with an alien invasion; it was inadvertently brought back by an unmanned space probe.
• Fragment: Hender's clover is a lichen-like flora of Precambrian origin which grows exceedingly quickly, secretes acid that can chew through rock, and can grow on practically any surface by changing its biochemistry to allow it to derive nutrition from even sterile plastics and metals. But the greatest danger of Hender's clover is that it's the base of the food chain on Hender's Island, and wherever it grows, much nastier grazers, larger (also predatory) flora species, and predators of the grazers quickly follow.
• The Genocides has the Earth transformed in a monoculture for alien crops, and the aliens consider humans to be pests and try to exterminate them. They succeed.
• Ward Moore's novel Greener Than You Think has the surface of the Earth being overwhelmed by a (human-created) variety of super-crabgrass.
• The Hexslinger Series: The Red Weed; unusually for such organisms, it actually enriches the land it infests — as long as you kill it by feeding it human blood, which oh-so-conveniently helps funnel power to the deities which seed it and encourages the practice of blood sacrifice in the locals.
• In Joseph Payne Brennan's The House on Stillcroft Street, botanist and Collector of the Strange Millward Frander brings a strange, purplish-green ivy with five-lobed leaves back to his hometown of Amley. However, it turns out the plant is sentient, grows wildly out of control and takes over Millward's house - and him! It acts like a Festering Fungus, turning Millward into a Jordy Verrill-style Plant Person/zombie. Millward's cousin Hugh Corvington ends the threat of the ivy by taking an axe to its roots, preventing it from spreading beyond the Frander house to infest the rest of Amley.
• Pandora's Star has the Primes flood the local lakes and rivers of the planets they invade with a single celled organism that is essential to their reproduction. The pollution of the waters like this kills off most of the other life in them.
• Project Hail Mary features a variation: spaceborne microalgae that migrated from a neighboring star system gathering on the sun to absorb its abundant energy. The so-called Astrophage reproduces at a rate similar to real-life bacteria, but with abundant resources and no predators or competition, doubling their population at roughly every eight hours. Their presence causes the sun to slowly dim, and scientists estimate that within thirty years, planetary cooling will cause a mass extinction and breakdown of social order as famine and cold start to take their toll.
• In Starship Troopers, the alien kudzu is from Earth; on Sanctuary, where there is almost no radiation, there is a very slow rate of mutation, so the native flora and fauna are simply overrun by Earth "more advanced" plants and animals.
• Played with in The Taking. Alien fungi overrun the Earth in what appears to be a massive attempt at rapid terraforming, but then the fungi promptly vanish and everything returns to normal. The "aliens" prove to be demons, whose transmission turns out to be a simple time-reversed message: "My name is Legion, is Abaddon, is Lucifer, is Satan, eater of souls."
• In Urfin Jus and His Wooden Soldiers, the mysterious plant discovered by Urfin Jus is definitely an example. It's thorny and nasty, spreads explosively, can take root basically anywhere, and can survive and grow even when chopped to tiny pieces. Only after Urfin uproots every single stalk, laying them out on a metal plate and leaving them to dry out in the sun, do the plants finally turn to dust... at which point it turns out that the plant's will to live is so powerful the dust itself animates anything it's sprinkled upon, which Urfin makes great use of in his plan to take over the Magic Land. Later on in the series, his house gets infested by the same plants a second time... but having since realized that Being Evil Sucks, he simply burns them all to ashes instead of creating more of the magic powder.
• In The Tommyknockers, the alien ship releases... something into the atmosphere which is harmful to almost any form of living creature that isn't a Tommyknocker, as part of their terraforming effort. Having metal in your head combats it.
• In Seanan McGuire's short story "Too Late Now", whose narrator outright compares the plot to The Day of the Triffids In-Universe, Earth is overrun by alien plants that outcompete all Earthly vegetation, and then start eating people and animals. Humanity is reduced to a few heavily fortified enclaves that rigorously search returning scouts for any trace of seeds.
• "The Voice In The Night" by William Hope Hodgson features Alien Kudzu lichen that covers an isolated desert island. It's a good thing that it's isolated, because the lichen grows on flesh as easily as rock: possibly the Trope Maker for combining Alien Kudzu with The Virus.
• In The War Against the Chtorr, Red Kudzu grows extremely quickly and can cover an entire town in weeks, and it shelters predatory Chtorran life forms. Attempts to control its spread through napalm strikes are negated in days by further growth, but massive amounts of human remains have been found before it reclaims the scorched ground. All attempts to permanently destroy it have failed, and it is resistant to all known poisons.
• The War of the Worlds (1898): As an Ur-Example of this trope, the Alien Invasion sees the Red Weed spread from Mars to Earth via the Martians' ships. Growing explosively, the Red Weed annihilates other plants and chokes rivers. It increases the sense of the Earth being overwhelmed, acting as a parallel for the Martians crushing human civilization and its military. It also serves to quickly foreshadow the end of the story: the chapter in which the Martians die begins with a comment that the red weed on the bridge to Lambeth's "fronds were already whitened in patches by the spreading disease that presently removed it so swiftly".
• In Stanisław Lem's short story "The White Death", a civilization of robots lives in a gigantic city beneath the surface of an otherwise barren world. When a crashed spaceship, with the remains of its human crew inside, is found on the surface, the king of the city orders it to be immediately destroyed and broken down into atoms. A single mold spore accidentally avoids destruction and subsequent widespread mildew infestation rises the humidity causing the whole civilization to succumb to rusting.

Live-Action TV

• The Avengers (1960s): In "Man-Eater of Surrey Green", a Man-Eating Plant from outer space lands in Middle England and takes several top horticulturists as its prisoners in an effort to germinate and spread across all of the Earth.
• Doctor Who:
  • "The Seeds of Death": The Ice Warriors employ pods that release a rapidly-multiplying spore, which sucks the oxygen out of Earth's atmosphere. The Doctor finds out that water counteracts the pods.
  • The Triffid-inspired Krynoids, from "The Seeds of Doom", which can possess Earth plants.
  • In the spinoff Class (2016), in the two-part episode "Co-Owner of a Lonely Heart"/"Brave-ish Heart", Earth is beset by rapidly reproducing flesh-eating pink flowers resembling cherry blossoms; their sheer volume will suffocate anyone they don't eat. They are never given a name other than "petals".
• In an episode of Eureka, the ice rapidly spreading over town turns out to be the result of the fungus growing in the ice.
• The final episode of Garth Marenghis Darkplace, entitled "The Creeping Moss from the Shores of Shuggoth", itself a likely Shout-Out to "The Lonesome Death of Jordy Verril" listed above, is about a virulent spaceborne ancestor of earthbound broccoli that infects and kills Sanchez's love interest.
• In Kamen Rider Gaim, the otherworldly Helheim Forest isn't just a side effect of an alien threat, it is the alien threat. Its spores come through spatial cracks and sprout up wherever they land, also poisoning the soil so nothing else can grow. Worse, anything that eats the plants' hypnotically delicious fruit is immediately mutated into feral creatures called Invess that spread its seeds. It's bad enough that the forest qualifies as an Eldritch Location that's already overtaken at least one alien world and is poised to consume the Earth in under ten years. In fact, it's heavily implied that the Tempting Apple and Food Chains tropes were inspired by past contact between Earth and Helheim.
• In Stargate SG-1 "Zero Hour", the base is infested with an alien plant that rapidly spreads given even the slightest amount of light. The effect is more obnoxious than dangerous, the point being to show the kind of nonsense O'Neill will have to deal with on a daily basis as the new base commander. The solution to the problem, however, inadvertently exposes another plan to trick Earth into blowing itself up.
• In Stargate Atlantis, the base gets seeded with the material of the organic ships used by the Wraith, and Wraith ship material begins to overrun the city, consuming the walls as raw material and tapping into any nearby power sources to fuel its growth. Worse, it was actually growing from inside one of the main cast. (She gets better, and more importantly, so does Carson, finally.)
• Double subverted in The X-Files episode "El Mundo Gira". After a bizarre flash of lightning and hot yellow rain, an immigrant farmer is killed almost instantly by what is discovered to be a normal Earth fungus (the mold Aspergillus) instead of an alien pathogen. However, the fungus multiplies rapidly when exposed to an enzyme of alien origin.

Music

• Genesis released a song called "The Return of the Giant Hogweed", about the said invasive plant which has had occasional outbreaks all over Great Britain. Of note is that the history of the plant in Britain, as narrated in the song, is entirely true — except for the part where they turn into Triffids and begin plotting their next invasion.
• Jeff Wayne's Musical Version of The War of the Worlds: "The Red Weed" is the first track on Disc 2, "The Earth Under The Martians." The music alone successfully conveys a silent, desolate London, wracked with scarlet fever (after a fashion) and choking to death from an alien life-form. Sir Richard Burton's narration is but the icing on the cake.

Tabletop Games

• Dungeons & Dragons:
  • Planescape:
    • Razorvine, which can mostly be found in the Lower Planes but eagerly acclimatizes anywhere. Its stem is a living razor wire, growing twisted and under tension, and thus lashing around if cut. Some try to use it as a security measure, but it's a virulent weed and hard to eradicate. In some places any sod barmy enough to bring in and plant razorvine cuttings can be summarily executed.
    • Egarus is a fungus from Abyss which was accidentally introduced on a Prime world, and after discovering that it grows everywhere and that the natives couldn't kill it, literal divine intervention saw the stuff banished to the Quasiplane of Vacuum... where it not only survived, it mutated to feed upon "nonexistence." Egarus quietly destroys (i.e. disintegrates) everything around it when it encounters other matter, but thankfully, it can no longer survive anywhere but the Quasiplane of Vacuum.
  • Spelljammer: Infinity vine is a leafless plant that, in light and air, will very quickly multiply its mass until it covers everything in a 10-foot-thick layer (there's not enough light beyond this). Of course, if the vines are covering a ship and the extra mass is more than its power source can pull, it's stuck for good. The vine is easily destroyed, but regrows almost instantly, and is immune to all diseases and poisons. Due to this magical metabolism it vanishes just as fast on planets and instantly dries up in the Flow — which is the only reason why the whole Prime Material Plane isn't buried under 10 feet of green ropes.
• Rocket Age: Oberon, a moon of Uranus, is said to be covered from horizon to horizon in a strange red moss that glows green at night.
• Warhammer 40,000:
  • The Orks are a fungoid hybrid lifeform that provides a weird variant of this. Each Ork constantly sheds spores (and releases a ton of them upon death) that usually grow into a variety of mushrooms that can be cultivated for various uses. But in certain conditions - usually if the spores land some distance from an established Orkoid community - those spores will also sprout first squigs, then snotlings, gretchin, and finally more Orks. Thus each Ork is a one-asexual-alien ecosystem, and any planet that has successfully repelled an Ork invasion will probably still be plagued by recurring tribes of Feral Orks for generations to come. The Departmento Munitorium, ever pragmatic, consider these worlds to be highly valuable as recruiting grounds, as guardsmen recruited from these worlds have a tendency to be disciplined, methodical, and "bloodied" in combat against Feral Ork tribes.
  • Tyranids are a more straightforward example. In the initial stages of a planetary invasion, a hive fleet will choke a world's atmosphere with spores that send the native flora into overdrive, sprouting more spore chimneys on the ground to accelerate the hothouse process. In the planet's last days, digestion pools will form, open-air stomachs that Tyranid organisms dive into to deposit consumed bio-matter, which is then piped up via capillary towers to the hive ships in orbit. And at the end, all of this is consumed and recycled, leaving nothing but a dead world behind.

Video Games

• The Bloom in 7th Dragon is brightly colored, spreads fast, and terraforms the planet for invaders.

• The Medusa Vines from Apex Legends's in-game comic "The Legacy Antigen" are this. They're utterly massive in size, easily spanning the length of multiple towering buildings, immune to bullets, fire, and freezing, aggressively grow to the point of threatening Olympus to crash, and release an airborne substance that can potentially trigger a fatal allergic reaction.
• The eponymous substance in the Command & Conquer: Tiberian Series serves to consolidate minerals and bring them to the surface in the form of green crystals that can be easily harvested and converted into whatever materials are needed. Unfortunately, Tiberium is highly toxic, and causes either death or mutation to all carbon-based life form afflicted by it, with almost no way to stop its spread. It was originally sent to Earth by the alien Scrin with the intent of looting the planet of its minerals after the Tiberium had killed the planet's original life, but GDI and the Brotherhood of Nod proved to be much tougher than they could've anticipated.
• Pops up in Dead Space — repurposing dead skin cells found in the dust of the ventilation system, something starts growing inside the ship, gradually transforming the atmosphere into something toxic for humans... even inside a hermetically sealed starship, it does a lot of damage and spreads widely. On a planet, it would get out of control in short order and swallow up everything. A scientist's log specifically describes it as a "habitat adjuster" or something like that... a biological terraforming engine, in other words.
• Deep Rock Galactic
  • The Hollow Bough biome is a subterranean Tree Trunk Tour that's been overrun by invasive red, thorny vines, ranging from thick sections wide enough to walk on (if you don't mind getting speared by thorns the size of swords), to spiny tangles that cut off passages but will rapidly retract into the walls if damaged (and slowly undulate back into position a moment later), to "Stabber Vines" that groan into position before thrusting at intruders (and if you destroy every vine in a cluster, something unseen screams in pain). This has left the rest of the biome a dead, brown place of petrified wood and enormous, maggot-like woodworms writhing in the walls.
  • Season Three introduces a "lithophage" known as the Rockpox, which as its name suggests is an infection of the rock itself. A passing comet is showering Hoxxes IV with chunks of contagion, which might land during normal missions and require calling in rock-breaking equipment to crack into the meteorite and recover the Plague Hearts within. If allowed to take root, those Plague Hearts will develop into Contagion Spikes that cover the surrounding terrain with a carpet of reddish-brown Meat Moss studded with spikes and yellow pustules, which can infect the local Glyphids into Parasite Zombies or even grow over and entangle any dwarf who lingers too long on the biomass. Dealing with these infected areas involves calling in a pod of cleaning equipment to decontaminate the area, but even when cleared, the Rockpox leaves a dark scar on the terrain. Making things worse is that the Rockpox is showing signs of intelligence, such as how the meteors falling to the planet seem to be deliberately targeting uninfected areas to spread the lithophage faster.
• Duke Nukem 3D had a non-interactive, non-controversial, and very olive-green form of this from Episode 2 onward. Then Duke Nukem Forever introduced the slappable titty walls.
• Elden Ring: The magical crystals known as glintstone were originally mined from fallen stars. That is, until it was discovered that unrefined glintstone spreads by transmutation, converting everything around it into more glintstone after enough exposure. Now the glintstone mines are vast and cavernous things, and are only kept from spreading across the Lands Between with containment spells. Whether through apathy or lack of knowledge, no such protection has been extended to the miners.
• In Evolva, the Parasite proves to be able to fill the whole planet with its mooks. Seriously, just compare the huge number of aliens and the number of indigenes you see in each level.
• Half-Life:
  • Toward the end of the first game you start to encounter organic bounce pads growing in Black Mesa.
  • In Half-Life: Opposing Force parts of Black Mesa are overgrown with some sort of organic matter native to either Xen or Race X homeworld. This biomass often provides ammo for Spore Launcher, attachment points for Barnacle Grapple and, in one instance, a Healing Pool.
  • Half-Life 2 has two fauna-based variations: the Antlions and the Leeches have overtaken most of Earth's landmasses and oceans, respectively. Barnacles are even more fitting example, as they seem to grow in every place with a ceiling and enough moisture.
  • Half-Life: Alyx takes place within the "Quarantine Zone" inside City 17. The whole area is infested with the usual barnacles, headcrabs, and antlions. There are even some varieties living there that aren't seen outside the zone. But the most worrying of all is the ever expanding Xen biomass growing uncontrollably, covering entire buildings and swallowing objects at a fast rate. The Combine have even made an entire cleanup force that fights these growths... to little success. These growths aren’t seen at any point in Half Life 2, implying the Combine were eventually successful in eliminating them.
• The Flood in Halo. It's a fungi-like parasite that takes over the bodies of sentient species and can convert an entire ecosystem into Flood biomass; when it takes over the Covenant capital of High Charity, the entire thing becomes covered in Flood kudzu. It has wiped out entire species, and forced the Forerunners to build the titular Halo Rings, and wipe out all life in the galaxy to start anew via reseeding various species they were able to index.
• One could only image what it would look like if The Beast from Homeworld Cataclysm were to make contact with a planet.
• Jak and Daxter: The Precursor Legacy: The Dark Eco Plant is an overgrown, heavily mutated plant creature whose roots have taken over the Forbidden Temple within the Forbidden Jungle. Defeating it in a Boss Battle will not only kill the monster, but also get rid of the roots.
• The Legend of Zelda: Tears of the Kingdom: Gloom is a toxic substance manifested by Ganondorf's dark power and an altered form of the Malice used by his Calamity Ganon incarnation from the previous game Breath of the Wild. Normally, Gloom takes the form of shallow, thin pools of concentrated darkness, but in possible contrast to Malice being Meat Moss, certain large concentrations of Gloom in the Depths sprout large twisted roots. Adding to this, Ganondorf's lair is a large complex of these gnarled roots.
• This makes up the entire ecology of Pragia in Mass Effect 2. It was a planet that was originally used for testing genetically engineered plants until the plants eventually got loose and infested the entire planet. By the time you visit it during Jack's loyalty mission the planet has been abandoned and is used exclusively as a base of operations by numerous Space Pirates, and Cerberus.
• Metroid Prime: Flaahgra, which is seeded in the Sunchamber, has many of its branches dominate a big part of Chozo Ruins, to the point of poisoning the local waters. After Samus manages to defeat the plant in battle, the place gradually reverts to its former glory.
• The omnipresent purple fungus from Mindustry, described as highly invasive and rapidly overgrowing the planet,^note The map editor even reveals that the solid-purple fungal terrain is in fact a fungus-infested forest, but also rich in oil for all your industrial needs. The game is rather cryptic about who is the aliens though, as both you and the opponent are Mecha-Mooks. Given the sci-fi theme, it's likely that both of you are.
• Minecraft:
  • The Sculk, located within the Deep Dark, can at best be described as a sort of glowing, eldritch moss that spreads by absorbing the lifeforce of creatures that die on top of it. Oddly, it's not dangerous on its own, and in fact 'player grown' Sculk is entirely harmless...what is dangerous is the extremely powerful Warden that spawns within the Deep Dark. The Sculk-covered Ancient Cities and their large portal structure also imply that the Sculk is not native of the Overworld and was brought there from another dimension.
  • The magic mod "Thaumcraft" has a magical kudzu called Taint. Not only is it quick-spreading and hard to kill, it can and will parasitize mobs and aura nodes (magic sources), causing them to turn hostile and spread the Taint.
• The solar system in Outer Wilds has four planets and Dark Bramble, what used to be a frozen world before some giant, gnarled, thorny plant took root on it and literally tore the planet to pieces, aided by the fact that flying into the wooden tangles reveals that the plant is much, much Bigger on the Inside. What's worse is that you can find a seed pod from that plant elsewhere in the system, suggesting that it might be trying to spread to, and destroy, other worlds.
• Pandora's Tower: The Treetop and Arcadian Towers are overrun with flora that originated from the large trees respectively seeded in their entrance halls. Originally, the flora was harvested by the military of Elyria to produce food and medicine, but the gravity of the war between the surrounding kingdoms left the tower in disrepair and the plants ended up growing out of control. As a result, many branches and vines obstruct the way, and Aeron has to kill certain thorny bushes to clear the path.
• Resident Evil: The Plant 42 is a huge, heavily mutated plant that reaches its state thanks to the T-Virus, as part of a series of experiments by the Umbrella corporation. Its branches have blocked certain doors, and have reached as far as the house of guests from the Spencer mansion.
• Quite a few variants of the Filth result in this during The Secret World:
  • Fungal Filth is this, spreading ghastly multicolored day-glow mushrooms wherever it goes: soil, concrete, buildings, native plantlife, even people (dead or alive) will be layered with the mushrooms. And that's in the event that the stuff is in the mood remain comparatively innocuous: if you're unlucky, it'll sprout legs and attack you.
  • Draug infestations are often accompanied by weird growths of red seaweed washed up on the beaches of the afflicted areas. It's essentially a form of plantlife native to the Draug's home environment deep in the Sargasso Sea, as Joe Slater — the only survivor of the voyage into the Isle of Dead Ships — reports seeing growths of red weed vast enough to have entire ships tangled up in it.
  • And of course, the standard "black tentacled slime" form of the Filth tends to sprout vinelike extensions of itself as it develops beyond its initial liquid form, until neighboring pipes, gantries and other surfaces are layered with creepers of the stuff. Taken to its logical conclusion in Tokyo, where pustules of the Filth can be seen extending vines several stories above the ground level.
• Xenofungus in Sid Meier's Alpha Centauri has these properties, but doesn't exactly count since it's native to Planet. On the other hand, one could argue that the human's terraforming efforts (particularly with stands of trees) are an inversion (Earth life infesting an alien ecology).
• One of the disasters in Sim Park is literally kudzu. Another one is Alien Invasion, which acts as an alien kudzu.
• Systems can be found in the Space Empires series that have been infested by some sort of titanic organism.
• In Space Station 13, "Space Kudzu" is a plant that spreads rapidly throughout the station and can only be destroyed by fire or suitable cutting implements. Fully grown Kudzu prevents anything from passing through the block that it is on. Not deadly in itself, but it's great at distracting the crew from looking out for assassinations and bombings.
• Star Control II mentions "Deep Children", modified Mycon used to terraform. They rapidly grow into the lower part of a planet's crust and provoke tectonic activity, making the planet a Fire and Brimstone Hell comfortable for Mycon but not the original species of the Mycon's preferred targets — organic-rich water-based worlds.
• The creep in StarCraft, which is probably supposed to represent this (although in-game it really only affects zerg base-building). In this case, the creep is not exactly an alien plant, but rather part of the Bizarre Alien Biology that makes up the zerg. It's closer to being zerg blood vessels than an alien plant. StarCraft II slightly alters the way in which creep spreads, making it considerably more invasive. Though the idea was scrapped for balance purposes, creep was even originally supposed to damage non-zerg buildings over time. It remains impossible for either of the other races to build on creep, though, making this trope in full effect.
• Super Mario Bros.:
  • Super Mario Sunshine: Petey Piranha grows thick, pulsating roots that infest the windmill that lies northeast of Bianco Hills. Mario has to avoid them as he makes his way to the windmill's top, where Petey awaits. After Mario defeats him, the roots disappear and the windmill returns to normal.
  • Luigi's Mansion 3: The Garden Suites has a tree that grew and extended to the point of turning the whole floor into an indoors forest. The overgrow is caused by a ghost, Dr. Potter, never ceasing to feed the tree with water.
  • Mario & Luigi: Partners in Time, in keeping with the War of the Worlds parody, has the purple alien mushrooms that the Shroobs spread over the Mushroom Kingdom. With their weapons and technology, the Shroobs can actually turn Toads and other Mushroom Kingdom inhabitants into these mushrooms.

• When the Prethoryn invade and infest a planet in Stellaris, it basically becomes this. The "Invasive Species" trait allows a plantoid or fungoid species (such as the primary species of the player's own empire) to be this, giving them extra habitability and growth speed for every negative trait they have.
• Terraria has The Corruption and The Crimson, evil biomes that spread this way. In the earlygame, these areas will steadily creep across the surface by converting adjacent grass into the purple or red flora of the biome, until the background changes to match and tainted enemies begin spawning. Once the player enters Hardmode, these corrupt zones spread even more aggressively - tainted trees and grass can spread over several-tile gaps, and worse, the Corruption and Crimson begins converting non-living matter like stone and sand to evil equivalents. In past versions of the game, this necessitated setting up "quarantines" to protect the jungle biome before entering Hardmode, otherwise the evil biomes would convert the jungle's mud blocks to dirt, destroying it. The Hallow, which appears when Hardmode begins, spreads similarly. In all cases, the player can use Purification Powder and the Clentaminator to purify these biomes to their original state, and there is as always an achievement for completely purifying a world.
• The Biomass in UFO Aftermath is an attempt to build a giant psionic brain by covering the Earth's surface in nerve tissue, and can be driven back with special base-sized psionic devices.
• The acid Cephad Zoa in Waking Mars eventually takes over any environment it's planted in, converting the fertile soil to an acid type so nothing else can grow.
• Warcraft:
  • Undead Blight in Warcraft III acts similar to Starcraft's creep, though there are differences- blight does not recede when its source is destroyed and can be dispelled by building structures of other races on or near blight.
  • In World of Warcraft, the Zangar Sea is home to a biome of fungal lifeforms. The Sea actively tries to invade the land and replace all other life, starting with transforming coastal areas into fungal forests which then attempt to spread inland.
• In War Metal, the Blight which is just like the vines in The War of the Worlds (1898), and it mutates any life forms it touches into Bloodthirsty.
• In XCOM 2: War of the Chosen, some wilderness around ADVENT facilities is surrounded by alien, bioluminescent plant life that wouldn't look out of place around a deep ocean trench. Since the Elders have no plans to xenoform Earth, it's easy to conclude that the aliens are just being careless.
• In Zombies Ate My Neighbors, the Red Weed found in War of the Worlds is an occasional enemy, though since it's sessile, it functions more as an expanding obstacle. The Red Weed is the focus of the stage "Where the Red Fern Growls," where it's the only enemy type and the goal is to rescue the people surrounded by the stuff. Weed whackers utterly destroy the stuff.

Visual Novels

• In Saya no Uta, one of the endings have this happen to the entire planet when Saya 'blooms'. Not just the planet but also humans are affected, in ways resembling Fuminori's Meat Moss perspective. This is appropriate, given that earlier in the story Saya compared herself to a dandelion spreading its seeds in a desert.

Webcomics

• One arc of Carry On has the USA becoming overrun by "kudzucchini" genetically engineered for terraforming Mars. It's eventually destroyed by an army of goats.
• Inverted in Freefall, the alien Sam Starfall comes from a planet where intelligent life developed early, so the life forms have had only limited evolution to develop defenses. He is terrified of Terran flora (or fauna) becoming this.

Web Original

• Dawn of Victory: The Scinfaxi weren't an alien "race" per se, but rather, a mutated form of life that, if left unchecked, would have turned Earth into a Death World, destroying all indigenous life and replacing it with its own twisted monstrosities. It did ultimately lead to the destruction of Earth's biosphere and the planet's abandonment, as humanity, once it had the technology to colonize space, evacuated Earth and then hit their homeworld with enough nuclear weapons to leave it a lifeless, irradiated rock in order to destroy the Scinfaxi for good.
• Hamster's Paradise:
  • The saberleaf is a type of grass originally native the the subcontinent of Borealia that incorporates slica into its leaves as a deterrent against herbivores, making them razor sharp and dangerous to eat or even just walk through. This, combined with its rapid reproduction become a huge problem when Borealia eventually connects to the mainland via continental drift. It overruns grasslands and causes several extinctions and displacements. It's only stopped when the ungulope, a grazing animal also native to Borealia, make their way to the mainland and which possess adaptations that let it safely eat the grass, keeping its numbers in check and allowing the mainland plants and herbivores to recover.
  • The coast kudzu is an oceanic grass that grows just as rapidly as its namesake and can spread several feet per day. It becomes very prolific during the Mid-Temperocene due to warmer climate resulting in an abundance sunlit, shallow seas that serve as a perfect environment for it. Unlike many examples of this trope however, its spread is actually a net positive for the ecosystem as it provides a home for many small creatures and its rapid growth serves as a food supply for aquatic herbivores, allowing marine grazers to reach sizes, numbers and diversity not possible in Earth's oceans.
• The Jenkinsverse: Earth life is so deadly compared to everything else that an alien ecosystem is slowly losing to human fecal bacteria.
• Orion's Arm: One way to terraform planets is to release plants like this on the surface where they will progressively alter the environment to suit human life.
• SCP Foundation has several examples of this. One of them is SCP-506, an inedible genetically engineered variant of zucchini that grows rapidly in increasingly harsh conditions. As long as there is organic matter it'll germinate.
• Serina:
  • Spikeleaf waterweed, a Tempuscene freshwater grass, evolves rapid growth and sharp silica-edged leaves to deter herbivorous fish and becomes an aquatic equivalent. If not regularly fed on by the giant gemnus, it can reduce entire waterways to choked marshes.
  • Assassin grass is similarly tough and fast-growing, with the additional aid of carrying poisons in its leaf edges to kill neighboring plants. Unsurprisingly, this makes it unpalatable to grazing animals, enabling it to comprise 99% of plant biomass in some places until the gluetrap tree evolves resistance to the grass and shades it out.
• Vita Carnis has this in the form of "Crawl", a meaty, vinelike substance that quickly takes over the world and from which the other creatures spawn

Western Animation

• Adventures of the Galaxy Rangers: "Marshmallow Trees" has shades of this, but by accident. The Kiwi ambassador is trying to share his planet's Fantastic Fruits and Vegetables with a human colony in the form of the titular trees. Unfortunately, while the trees are tested and found to be perfectly safe on Kirwin, the conditions of the colony world causes them to grow out of control.
• Jayce and the Wheeled Warriors: The Monster Minds have vines which not only grow all over, but between planets in interstellar space.
• Kipo and the Age of Wonderbeasts: Fun Gus is a sentient mutant slime mold that has infested the burrow where Kipo was born. What’s worse is that it has the mind of a Creepy Child and is eager to “play” with anyone who stumbles into the burrow… forever and ever.
• During the Grand Finale of The Owl House, Emperor Belos fuses with the Titan's heart, this causes the Boiling Isles to quickly get covered in hideous amount of green mold that kills anything it touches.
• The Legend of Korra: After the climactic events of season 2, dense forests of spirit vines have taken over sections of Republic City. Korra’s inability to permanently remove them becomes a source of tension that leads to her seven percent approval rating at the beginning of season 3.
• My Little Pony: Friendship Is Magic: In "Princess Twilight Sparkle, Part 1" and Part 2", Equestria is being taken over by Plundervines, which grew from seeds planted by Discord shortly before the Royal Sisters sealed him away, but were kept in check by the Tree of Harmony's reserve power, which is running out. Once the Tree's magic fails, they begin to grow at a fantastic rate, quickly overgrowing the Everfree Forest and Ponyville and proving too tough and fast-growing to eradicate, in addition to developing abilities tailored to interfere with pony magic.
• Steven and his mother Rose Quartz in Steven Universe are both arguably walking sources of Alien Kudzu. Their bodily fluids, in addition to healing organic lifeforms and Gems alike, creates new, often sentient species out of plant life it comes in contact with, such as the Watermelon Stevens and Pumpkin. Steven must be amazingly careful where he spits, or else the Earth would soon be overrun with invasive fauna!
• The Transformers had Morphobots, alien robotic robot-eating plants that spread quickly enough to fill an entire valley in a matter of hours, in "Quest For Survival". The Autobots ship them all off to a planet infested with robotic insects, after the Morphobots eat all the Insecticons' clones.
  Bombshell: You didn't tell us they bite back!
  Megatron: But those three ingrates got away!

Real Life

• The Trope Namer is kudzu, aka the Vine That Ate the South.
  • It was brought over from Japan to the Southeastern United States to prevent soil erosion along railroad trackbeds, it was quickly realized that it grows over large patches of ground, choking out native plant life by denying it sunlight and nutrients. It also loves growing over trees, choking them to death in shade, pulling down branches, or just outright uprooting the tree. It happily does the same to utility poles and power cables, which causes all SORTS of problems. Its growth is roughly a foot per day; take a trip for a week, come back to find it's covered an entire wall of your house. And the seeds can take years to germinate; if you can kill the notoriously hardy thing, you'll often find out a year later that its children have returned for revenge. Oh, and it prevents soil erosion along railroad trackbeds.
  • Then we have Imperata cylindrica, also known as Cogon Grass. This literal red weed chokes more acreage in the southeast than even the more infamous Kudzu and, while not having quite the impact on the environment as kudzu, it is unusually flammable.
  • Going back farther, when European settlers first came to the Americas, they brought several plant species with them. Normally not thought of as being aggressive, when introduced to the environment, they went absolutely berserk. Before kudzu, the Deep South was overrun with peach trees (see the correlation between peaches and the state of Georgia), and Argentina was smothered under feral spinach. That said, being edible, these weren't as bad as kudzu. (Technically, kudzu is also edible, but that requires a lot of processing and is a pain.)
  • In the Pacific Northwest, there's been a lot of work done for decades to prevent a pair of European plants, Scotch Broom and Gorse, from becoming this. Success has been poor: Scotch Broom is toxic to local herbivores while Gorse happens to be Made of Explodium — it catches fire very easily and burns extremely hot.
• You've got kudzu? The Soviet Union will one up you with giant hogweed, also known as Stalin's Revenge! This thing is just as easy to grow, and its sap is a potent, insidious, slow-acting poison causing burns like mustard gas! It can kill kids who don't know better and tamper with it. It's also fifteen feet tall and grows in massive growths of hazardous shrubbery, like some toxic alien jungle. You have to wear a hazmat suit if you want to clear a patch of this plant monster.
  • Oh, and it's moving into Upstate New York. You know, the place with a significant portion of its economy based around hikers in the mountains. Did we mention giant hogweed looks like most of the plants in the carrot family, which are also in NY?
  • And its smaller but deadlier cousin, poison hemlock, otherwise known as the plant used to kill Socrates.
• Zucchini. They will overrun your garden if you aren't careful. So will their cousins, pumpkins, and certain wild-type cultivars of strawberries — which spread by sending out runners that root themselves and grow into a new plant, so that each plant can generate two or three new ones every year — can be rather surprisingly challenging to keep contained. As useful (and tasty) as these plants are, they can be a bit of a nightmare to confine to just a single vegetable patch or flower bed.
• Blackberry plants (aka Brambles) are remarkably fast growers, being able to grow from a single seed into a sprawling network of very thorny and very, very robust stems and branches. They can also grow in soils of very poor quality, regrow steadily after being cut back, and their roots reinforce the soil. While these properties makes them very useful for both their fruit and as a way of enforcing boundaries around the garden, they can also very easily overrun their initial patch, creating an impressively large and undeniably painful hazard to contend with.
• Anyone who has a cottonwood tree in the vicinity of their yard knows how quickly your yard can be inundated by stray saplings. Not exactly alien in areas where it's native, but it's still a hassle to pull the excess of saplings out of your lawn.
• Caulerpa taxifolia, a type of seaweed running rampant in the Mediterranean Sea. The aquarium strain that went invasive thrives in polluted waters where other marine plants can't compete with it and is thus able to quickly dominate ports, tourist beaches and other human-influenced areas, it's inedible to most animals, and any small fragment is capable of taking root and growing into a new plant — in practice, this means that any anchor or ship's hull with a few leaves stuck to it can spread the plant and seed a new, full-scale infestation elsewhere. The one upside is that it filters out pollutants to feed on them, meaning that large patches of this stuff are capable of noticeably cleaning the water they grow in.
• Water weed (Elodea) was nicknamed "water plague" after its introduction in Europe and Russia for its habit of growing into a sargasso in still or slow-moving waters.
• The prickly pear cactus was this in Australia for a time. Originally introduced as an effective and self-repairing barrier for large cattle stations it eventually grew out of control and choked off the fields it was meant to guard. It was finally brought under control by the introduction of the Cactoblastus moth which eats it (and unlike the infamous cane toad, local insect eaters will eat them just as readily as native insects). A rare case of introducing a species to Australia that actually worked.
• Japanese knotweed, as well as its close relative, Giant knotweed. Both are popular garden plants that can quickly fill up the whole garden if allowed to grow unchecked. In the UK, a single plant growing in your garden can ruin your house's mortgage value and it has to be disposed of like a biohazard rather than disposed of in landfill. It can also reappear up to 10 years after being dug up if any root fragments are missed. "Popular" isn't the right term...
• Mentha spicata, or spearmint, is grown in pots, otherwise it does this — but underground.
• If kudzu is the vine that ate the South, then Himalayan blackberry is the vine that ate the Pacific Northwest. Fortunately, it's not quite as fast growing and isn't toxic or prone to exploding in flames, but the thorns that grow on its vines and leaves make it unpopular with most browsing animals. Birds and small mammals love its delicious berries, but this just means that its seeds are deposited in a nice pile of fertilizer. It does have one major enemy that's proven quite effective at controlling it, though: goats. Goats will happily eat its leaves and even vines, quickly destroying the plant. So by putting up some temporary fences around an overgrown area and leaving goats to take care of the vines, it can be quickly eliminated with relatively low impact to the environment (compared to other methods of control such as burning it or using chemical herbicides).
• While neither fungi nor plants, the Quagga mussel and Zebra Mussel fit this trope to a T. They are invasive species that came to the Americas as larvae in ship ballast tanks, they expand onto any surface they can find, hard rocks and metal and muddy bottoms alike (which has caused problems when they clog intake pipes), and because of their sheer numbers they consume huge amounts of food, which destroys the phytoplankton population of any body of water they settle in. This in turn can cause the collapse of the native food webs of the areas they infest, as the removal of the phytoplankton essentially starves the entire food web from the bottom up.
• Many in the U.S. fight the annual battle with crabgrass and dandelions in their lawns.
• Outside of its native habitat, garlic mustard (Alliaria petiolata) produces hundreds of seeds per plant, kills soil organisms needed by other plants while "terraforming" the area to its own liking, and is unpalatable to many herbivorous animals.
• Water hyacinths (Eichhornia spp.) quickly crowd waterways, choke out other plant life, and may even deoxygenate the water enough to suffocate fish and other aquatic animals.
• Technically, none of us would be here if not for the original Alien Kudzu, cyanobacteria (a.k.a. "blue-green algae"). Before they evolved, Earth's atmosphere was virtually free of oxygen and anaerobic Archaea dominated its ecosystems. Once they started spewing out volatile oxygen as a byproduct of photosynthesis, they took over the world and drove the oxygen-intolerant Archaea into niche habitats like hot springs, hypersaline waters, or deep under the ocean floor. The chloroplasts of modern plants are their distant descendants, so one could argue that all vegetation is Alien Kudzu from the Archaea's POV.
  • It's important to note that cyanobacteria continues to be Alien Kudzu, even today. Under certain conditions, cyanobacteria can reproduce explosively, creating harmful algal blooms that can have dramatic ecological effects, like killing off every fish in a lake. Some species of cyanobacteria also produce cyanotoxins that can cause health problems for humans, which is especially concerning when cyanobacteria grow in water reservoirs used for human consumption, as the water undergoes treatment prior to consumption that removes harmful microbes like cyanobacteria, but doesn't remove any cyanotoxins that may have been released into the water. And if you're wondering why this happens, take another look at the name (hint: there's a reason it's called cyanide).
• Some plants could be considered that if they weren't so damned useful. Potatoes, for instance, originally came from high up in the Andes (and most types of them do not grow anywhere else), but almost everybody who lives in a temperate climate can tell tales of thrown-away potatoes suddenly germinating on their compost heap. Those tubers are hard to kill, easy to grow, and so nutritious that Ireland basically ran on them for a century, until a disease killed most of them and caused one of the worst famines in European history.
  • The famine that hit Ireland also hit other parts of Europe, particularly France, Germany, and the Austrian Empire. However, both of those countries still grew significant amounts of grains, while in Ireland the landowners had converted most of the grain-growing land to cattle-raising land to satisfy English demand for beef, cheese, and butter. (There was enough food in Ireland to have lasted the population through the famine, but much of it was claimed by the English - the potatoes were one of he only crops the Irish were allowed to keep.) On the other hand, though, France, Germany, the Austrian Empire, and non-Austrian Italy also suffered bad grain harvests in the mid-1840s. This is why the decade is often called the Hungry Forties, and also a big reason why a wave of revolutions hit Europe in 1848. (Mike Duncan has a decent survey in Season 7 of Revolutions, devoting an entire episode to the topic.)
• In Finland, the local plant invader is lupine. It was imported in 1700s as a garden plant. Since then it has spread everywhere and there are very few stretches of roadside that don't have at least some lupines. Lupines have a nasty tendency to pump so much nitrogen into the soil that it chokes out any other kind of native plant, except, naturally, the ones which were already nuisances, like nettles and willowherbs.
• Black locusts are a benign-ish example (think the peach in Georgia) in Hungary among other places it was taken from its native habitat (an area in the US). It reproduces rapidly and can quickly overtake other tree colonies... but its wood is very good both as fuel and for other things, and its flowers are really beloved by the bees, producing delicious honey.
• On the other hand, ragweed can be the bane of your existence not only if it takes root in your garden, but also if you happen to be one of the many people allergic to its pollen.
• Tumbleweeds are an invasive species in the Americas, likely brought over from Russia by accident as part of a batch of imported seeds, and cause massive problems for American agriculture (including, but not limited to, being able to reproduce in huge numbers from a single specimen, leeching nutrients from the soil that other plants need to survive, being covered in thorns that can cause painful injuries to farm animals and humans, and being highly flammable, meaning they spread wildfires and are difficult to remove with machinery). CGP Grey's The Trouble with Tumbleweed looks at some of the problems they cause.
• Certain fungi cause Witch's broom disease, because they spread over a plant and cause it to dry while being covered in shoots, making it resemble a broom. It's particularly lethal for cocoa trees, as shown first in Ecuador and later, Brazil - the state of Bahia, once afflicted by WBD, saw its cocoa production fall from 380,000 metric tons per year to 90,000 metric ton a decade later, ruining the local economy (the country's chocolate industry even had to start importing cocoa seeds).
• Species of Lantana are this in Asia, Africa and Australia. Lantana form dense, spiny thickets that crowd out native plants, alter fire patterns and even provide shelter to disease-spreading insects. It doesn't help that their leaves are poisonous to most animals. On the other hand, their flowers and fruit can provide food to native animals.

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