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[[caption-width-right:350:"We must scour them from the stars before they do the same to us."]]

->''"An alien threat has risen from beyond the abyss, a swarm so vast that it blots out the stars. This horror fights neither for power nor territory, but rather to feed a hunger so insatiable that it will eventually devour the entire galaxy."''
-->-- '''Inquisitor Lord Kryptman'''

In ''TabletopGame/Warhammer40000'', the Tyranids are an extragalactic swarm of aliens that doesn't just overrun worlds, but [[HordeOfAlienLocusts consumes everything on them]] right down to the bedrock, including the oceans and air. Tyranids are more of a virus than a species, as they instinctively scan the DNA of what they eat and apply useful evolutionary upgrades to their swarms, ensuring that they only grow more deadly with each victory. Everything they use, from ranged weapons to spaceships, are [[OrganicTechnology symbiotic organisms]], to the extent that it can be hard to tell where a Tyranid "gun" ends and the creature carrying it begins.

Though the individual creatures in the Hive Fleets are little more than beasts, Tyranids are controlled via synapse creatures by the race's HiveMind, which is ''extremely'' intelligent. While the classic Tyranid strategy is to overwhelm their foes [[ZergRush with weight of numbers]], the swarms have also been seen to ambush armored columns in narrow passages that turned tanks into helpless sitting targets, employ burrowing organisms to launch surprise attacks behind enemy lines, or use winged creatures to sow discord and confusion. Of particular note are the specialized Tyranids known as Genestealers. They implant their DNA in victims, turning their children into [[HalfHumanHybrid Genestealer/human hybrids]] who will eventually form a cult on their homeworld that undermines the planet's defenses while psychically summoning the swarm. Three Hive Fleets have been encountered thus far: Hive Fleet Behemoth nearly overran the Ultramarines' homeworld of Macragge and killed their entire 1st Company; Hive Fleet Kraken all but wiped out the Eldar of craftworld Iyanden; and Hive Fleet Leviathan is currently rampaging through an Ork empire, as well as threatening the Blood Angels' homeworld of Baal... and these are likely just the vanguard of more Tyranid swarms still en route to the galaxy. The optimistic take on the Tyranids is that they are moving on our galaxy after cleansing one or more other galaxies of life. The pessimistic take is that they are running from something worse.

The tabletop Tyranid army is a mix of swarms of highly-expendable critters able to swamp even Imperial Guard or Ork forces, backed up by lumbering monstrous creatures capable of tossing tanks around with their tusks or blowing up heads with psychic powers. They also contain units of specialist creatures able to infiltrate or move quickly in order to keep the enemy occupied in close combat while the rest of the army closes in, and the biomorph system allows units to be upgraded to deal with specific targets rather effectively. The Tyranids' two main weaknesses are comparatively few ranged units, as well as the reliance on a few synapse creatures to keep the swarm together. The latter is offset by the fact that the presence of said creatures makes the rest of the army fearless, and the former rarely comes into play as the standard Tyranid strategy is to roll over the enemy like a tsunami.

The Tyranids have been a part of the ''Warhammer 40,000'' universe since the 1st Edition of the game and have received rules in every edition since. The Tyranids have made appearances in a number of [[GaidenGames spin-off games]] and computer games including the 1993 board game ''Doom of the Eldar'' that focused on their invasion of the Craftworld Iyanden. The Tyranids of Hive Fleet Kraken were also the antagonists in Games Workshop’s first ever worldwide campaign, the ''Battle for Ichar IV''. The 8th Edition rules for the Tyranids can be found in November 2017s ''Codex: Tyranids''.

!!Notable Tyranid tropes include:

[[folder:Hive Fleets]]

* TwoDSpace: Averted with Hive Fleet Leviathan. The Imperium was perplexed by Tyranid attacks taking place far behind the "front line" at the galactic "east," until they realized that the Hive Fleet had ''flanked'' the galaxy and was attacking "upward" from "underneath" it.
* AbnormalAmmo: ''Everything'' the Tyranids fire. The most conventional are things like [[SpikeShooter spikes]], [[PlasmaCannon bio-plasma]], and [[HollywoodAcid acid]], but even those are outnumbered by LivingWeapon ammo which in turn is launched by (or more properly [[WeaponizedOffspring birthed from]]) another LivingWeapon.
* AbsurdlySharpClaws: Any Tyranid strain from the Genestealer up has zero problem cutting through PoweredArmor, and the big ones can tear open tanks.
* AcidPool: Digestion pools created and maintained by the Tyranids on invaded worlds. Tyranid organisms (especially ones which have been consuming the local environment) will throw themselves into the pools to be rendered down into biomass to be reabsorbed by the hive. Smaller digestion pools will eventually be drained by capillary tendrils through the ground to empty into a vast digestion ocean. This ocean will then have feeder tendrils dropped into it from hive ships from orbit, as a kind of temporary suction-based SpaceElevator to finally absorb the biomass back into the fleet.
* AdaptiveAbility:
** As part of their fluff, this is what makes the Tyranids so dangerous; they constantly mutate and evolve to counter any weapons or tactics brought to bear against them, as well as [[CannibalismSuperpower absorbing the genes of other lifeforms to increase their options]]. Prior editions hinted that every Tyranid lifeform encountered is an offshoot of one of the main races; Zoanthropes are born from Eldar, Biovores from Orks, the basic genestealer from humans, and Tyrant Guards from Space Marines.
** However, this is also a weakness; in theory, a successfully strained Hive Fleet could be pushed so hard that they use up all of their harvested biomass faster than they can replenish it, and/or end up mutating into MasterOfNone strains in their quest to become JackOfAllTrades. This is exemplified by Hive Fleet Gorgon, the only canonical Hive Fleet to focus on the Tau, so far. Because the Tau, unlike the Imperium, are constantly redefining and reinventing technology and tactics, Gorgon was pushed to extinction; unable to replenish its biomass as fast as it was depleted, and incapable of producing the larger, vital synapse creatures needed to control its smaller, more simple-minded spawn, the Tau were able to whittle it down. The surprise addition of an Imperial Fleet, and a hasty, reluctant treaty between humans and Tau, was the final nail in the coffin. Gorgon found itself torn between which race to evolve to counter and unable to focus, so it was torn apart and driven into deep space, where it took decades to recover.
* AlienKudzu: As a Tyranid invasion of a world ramps up, self-replicating organisms are landed on a planet to begin initial biomass consumption, as well as pumping out smaller scale creatures for both scouting and undermining defenses and helping to [[{{Terraform}} render the rest of the world's biomass into a more easily edible form]].
* AllWebbedUp: The result of the strangleweb bio-weapon, which sprays [[CoveredInGunge a viscous mucus-like substance over targets]]. Shortly after projection, the substance hardens into a solid resin while shrinking down and constricting. Fragile targets can be crushed by this, and the more a target struggles and moves, the more opportunity the web has to constrict around it.
* AlwaysChaoticEvil: Or rather, Always Extremely Ravenous. While the HiveMind of the Tyranids possess some obvious, albeit utterly alien, intelligence, there is no way of communicating with it, no way of dissuading it, and no reasoning with it. It is driven to violently consume biomass, and nothing can change that.
* AntiAir: The Hive Crone, the Tyranid equivalent of a fighter jet, is armed with tentaclids that can reroll failed hit rolls against flying enemies.
* AntiMagic: All Tyranid synapse creatures dampen psychic abilities around themselves with the Shadow in the Warp, but Hive Fleet Kronos, as the Hive Mind's chosen response to mounting daemonic incursions, is the most advanced. Its suffocating presence smothers psychic powers, withers daemonic creatures, and closes Chaos portals.
* ApocalypseHow: Every planet they conquer gets a Class 6, and unless some way is found to break the Hive Mind, the same ''will'' happen to the entire Milky Way galaxy.
* ArtEvolution: Compared the Tyranid models from [[http://i5.photobucket.com/albums/y163/schepphimself/TyranidWarriors.jpg 2nd Edition]] with the ones from [[http://wh40k.lexicanum.com/mediawiki/images/d/d9/Tyranid_Warriors.jpg later editions]]. Earlier Tyranids had more biological variety too, until their redesign gave the race a more unified look, such as adding boney ridged crests on almost every head.
* AttackAnimal: The lesser Tyranid creatures qualify, having little independent intelligence and only minimal (though often brutal) instinct to guide them. However, they have "handlers" in the form of synapse creatures, which are both more individually intelligent and capable of interfacing with the HiveMind at greater distances, giving psychic "commands" to the lesser creatures as long as they remain nearby.
* BladeBelowTheShoulder: Type 3 for some Tyranid melee units, which have their arms below the elbow replaced with long [[SinisterScythe scythe-like]] talons, tapering down to [[SharpenedToASingleAtom a monomolecular edge]] like most of the blades in this setting. Note that older editions also had some units in which a bone-like blade was simply gripped in hand in the manner of a sword (and the Swarmlord special character still does this) but ArtEvolution has merged most of these weapons into their wielder, putting them into this trope.
* BigBad: A serious contender for the setting as a whole, though it would be difficult to define the HiveMind as a ''singular'' "Big Bad". That said, their race/species is absolutely bent on consuming ''all'' of the Milky Way galaxy, right down to the last scrap of biomass, regardless of whom if belongs to. The sheer size of the real invasion fleet (the three Hive Fleets that have already shown up are apparently ''just scouting parties'') means every other faction would need to either unite to stop them, or call a cease fire to combat a mutual enemy, just to survive.
* BlueAndOrangeMorality: While they are an immense menace to the galaxy at large, their motive is basically summed up as "we're hungry", which is hardly an evil impulse. They just don't seem to care at all about every other living organism in the galaxy, and might not even realize that other races are sentient. It's telling in a universe where Chaos has its hand in everything that the Tyranids managed to be immune to their whispers (likely because not even Tzeentch can understand them). Although it may just be that the Hive Mind is on a level with them.
* BrainFood: Any Tyranid creature with lamprey-like feeder tendrils in place of a mouth will be likely to eat brains. Lictors in particular are known for doing this, as it allows them to sift though a consumed organism's memories for information. This is part of a Lictor's role as a vanguard organism, helping the Hive Fleet gain intelligence on what worlds would be good targets for consumption and what kind of defenses to expect.
* BreathWeapon: Some critters can make bio-plasma attacks, vomiting up a blast of white-hot energy accompanied by a piercing screech.
* BugWar: If your Tyranid problem has gotten beyond the Genestealer Cult stage, [[EndOfTheWorldAsWeKnowIt you're pretty much screwed]].
* BulletSeed: A near-literal case with many of the more rapid-firing {{Living Weapon}}s wielded by some Tyranid organisms. Except that the "seeds" are things like tiny beetles which bore into flesh, or little worms which secrete acid and melt themselves into a target.
** In one literal case, the Tyrannofex has the Rupture Cannon which fires two rounds: a bloated tick... and a seed case. Fluff says the two react in a catastrophic fashion when their chemical fluids are mixed upon impact.
** Another literal one is the Barbed Strangler/Stranglethorn Cannon. It fires a seed pod that sprouts into a mass of fleshy tentacles in an instant, strangling whatever is within its reach. It has immense strength, but poor armor penetration because stronger armor can simply shrug off its attempts.
* CastFromHitPoints: The Harridan and Hierophant's Frenzied Metabolism special rule allows players to have the creature suffer wounds in exchange to temporarily making its bio-cannon stronger.
* ChestBlaster: An option for some offensive biomorphs. Tyranid models will occasionally mount flesh-hooks or devourers underneath some folds on their underside between their forelimbs.
* ColonyDrop: Hive Fleet Jormungandr employ a unique method of planetary invasion, seeding asteroids with tunnelling and vanguard bioforms and then launching them at a prey world. Those asteroids that make it through the world's orbital defence network spread Tyranid creatures across the planet that, which then go into hiding until the majority of the Hive Fleet makes its assault, striking the prey from an unexpected quarter.
* CombatTentacles: Ranging from lash whips and flesh hooks on the battlefield creatures to tentacles on ''spaceships'' for boarding actions.
* CombatPragmatist: Unsurprisingly, since the HiveMind has no need, use or real understanding of something like fair fighting, no more than a hungry animal would. As long as the result is more biomass for the Tyranids, it will employ any means necessary. One classic example of this was when the Avatar of Khaine attempted to challenge the Swarmlord synapse creature to a [[LetsFightLikeGentlemen duel]] on Craftworld Iyanden. The Swarmlord promptly sicced [[ZergRush a dozen Carnifexes on it]], quickly overwhelming it.
* CompositeCharacter: Imagine a merge of the [[Franchise/{{Alien}} Xenomorphs]] and the [[Film/StarshipTroopers Arachnids]]. [[OhCrap You may weep now]].
* CounterAttack: Any unit which inflicts wounds on a Pyrovore, Toxicrene or Haruspex in close combat suffers mortal wounds itself from their acidic blood.
* DeadlyGas: Tyranid spore chimneys (rigid towers grown from the ground) spread microbial spores on the wind to take seed and grow into more Tyranic bio-forms. Some Tyranid units also have biomorphs that cause them to discharge neurotoxic gasses that are lethal to non-Tyranid lifeforms. Then there is the Venomthrope genus, which produces a deadly gas so thick and opaque it is hard to even make out its profile through it all.
* DefeatEqualsExplosion: The stomach of a Pyrovore is full of highly volatile, acidic bile that can explode if exposed to the air. The 8th Edition of the game represents this by giving the Pyrovore a 50% chance of exploding when killed, dealing [[UnblockableAttack mortal wounds]] to nearby enemy.
* DigAttack: The Tyranid Trygon has the ability to dig underground and execute a devastating attack on the troops above it as it surfaces.
* DoesThisRemindYouOfAnything: Some Tyranid ranged weapons feature [[{{Squick}} sphincters and muscle spasms ejecting spurts of hot liquids]]. Depending on the model, it can either range from subtle (such as the humble Fleshborer) to dick-wavingly obvious (such as the Biovore, which one reviewer noted is basically teabagging itself with its own nutsack).
* DropPod: The mycetic spores or tyrannocytes are essentially OrganicTechnology versions of these concepts. Living creatures violently birthed from hive ships with other Tyranid organisms nesting inside them, they crash into planets and disgorge their living contents. Even then, they often have some further utility, such as bio-weapons to defend the area, or the ability to (slowly) move or burrow, sometimes spouting microbial spores onto the wind or becoming another womb for gestating more Tyranids.
* DumbMuscle:
** Carnifexes lack the hivemind connection of Tyranid synapse creatures. In their case this is a LogicalWeakness: their brains are small and well-protected to avoid having [[BoomHeadshot an easily exploitable weak point]] so they can withstand massive damage. Even then it is not much of a liability, as deprived of synapse guidance, its instinct tends to [[TheJuggernaut just keep plodding forward and knocking things over]].
** Likewise Tyrant Guard, who are biological {{Stonewall}}s, have small brains for the same reason Carnifexes do: [[JustifiedTrope less vulnerability to careful shots]]. The fact that they always operate in close proximity to a synapse creature (a Hive Tyrant) means that they can benefit from its intelligence via PsychicLink, and thus do not need to be very smart.
** Most Biotitans that lack synapse are this, as their sole intent was to cause as much carnage and destruction as possible. Giving them a smaller brain not only helps them survive otherwise fatal headshots, but also means that they have only one overriding purpose in life (and are oh so very easily pissed off).
* EatingOptional: Most Tyranid organisms don't actually have a functioning digestive system, as they're bio-engineered killing machines and such a thing would take space and energy away from muscles, reinforced endo- and exoskeletons, weapon-biomorphs, etc. If they aren't killed by the enemy first, they will eventually starve to death. Many of them still have instinctive behaviour to feed, though, as it makes them attack the enemy even when not under control of the synapse creatures. The Ripper swarms are the most obvious example, as their whole purpose is to eat any biomass they come across in order to transport it to the reclamation pools to be digested and fed to the Tyranid hive ships. The one major exception is the Haruspex, which is specifically designed to eat everything in its path as part of the Hive Mind's strategy to consume as much biomass as possible.
* EmpathicWeapon: In a quite literal way. The {{Living Weapon}}s employed by the smaller Tyranid genus types symbiotically bond with their wielder, melding their flesh together and growing spinal cord-like attachments to mesh their nervous systems together. In this way, the weapon itself acts as a sort of secondary "brain" for the creature, giving the limited intellect of its primary brain the knowledge and skill necessary to use the weapon. The Pyrovore takes this to an extreme; the weapon is sentient but the body is not. The Exocrine is essentially a big walking weapons platform for an organic artillery cannon.
* EnemySummoner: The Tervigon is a walking Termagaunt factory, birthing them directly from its belly to go into battle. In-game, every shooting phase the Tervigon produces 3D6 Termagaunts, only stopping if doubles are rolled.
* EnemyToAllLivingThings: Well, all ''other'' living things. Tyranids are inimical to all other forms of life, often [[AlienKudzu choking it out via their own reproduction]], and even their bodies are toxic for other lifeforms to ingest. They're considered so bad that -- aside from the Genestealer Cults that are Tyranid spawn -- [[EveryoneHasStandards no faction will partner with them]], and that [[EnemyMine many enemy factions will team up in the face of the threat they pose no matter how much they hate each other]].
* EverythingsBetterWithDinosaurs: The big ones are often described as dinosaurs.
* EvilEvolves: Characteristic of the Tyranids is that they evolve and [[AdaptiveAbility adapt to overcome stubborn resistance]]. Some of these adaptations are taken from [[PlanetEater consuming worlds]], where the Norn Queens in the fleet [[LegoGenetics sift through the collected genetic data looking for useful characteristics]] to incorporate into future generations. Others are adaptations that occur in the field, allowing the swarm to overcome specific difficulties by targeted mutation. Such evolution, though, inevitably tends to result in some NecessaryDrawback weakening them in one regard while it strengthens them in another. As the smaller creatures have a much shorter lifecycle and gestation time, a hive fleet that is heavily adapting will tend to be composed of a [[ZergRush greater proportion of smaller units]], leaving a shortage of [[HiveQueen synapse creatures]]. This can become a potential weak link in their force structure, which is why not all hive fleets take that approach.
* ExplosiveBreeder: Larger organisms {{avert|edTrope}} this, as they take a non-trivial amount of time to gestate and fully mature, especially the brain-heavy [[HiveQueen synapse creatures]]. However, the smaller and less neurologically complex Tyranids can breed extremely quickly, with the swarm able to reinforce its supply of lesser creatures in a matter of days, provided it has sufficient biomass.
* {{Expy}}: In many ways, especially with the overall design of Genestealers and [[http://img3.wikia.nocookie.net/__cb20121023045459/warhammer40k/images/3/3b/Norn_Queen_Concept_2.jpg this concept art depicting a Norn Queen]], the Tyranids are [[SincerestFormOfFlattery practically a walking tribute to]] [[Franchise/{{Alien}} the Xenomorph]] designed by Creator/HRGiger.
** They are also strongly reminiscent of the Bugs from ''Film/StarshipTroopers'', including their use of specialised subspecies for certain roles.
* ExtremeOmnivore: The Hive Fleets leave nothing but lifeless, airless rocks in their wake.
* EyelessFace:
** The bio-forms based on the Tyrant Guard genus all characteristically lack eyes and other sense organs which might be a vulnerability. Since they are bred to always be close to other perceptive Tyranid creatures with whom they share a PsychicLink, this is not as big a disadvantage as it would seem.
** Zoanthropes and Neurothropes also lack eyes, although in their case it's because they no longer have need for mundane things like sight for perceiving the world.
* FatteningTheVictim: As well as [[HostileTerraforming seeding Tyranid flora]], the masses of spores that the Tyranids release into a prey planet's atmosphere during an invasion encourages the native life to proliferate so that the ecosphere produces the maximum amount of biomass for the Hive Fleet to consume.
* FireBreathingWeapon: The flamespurt is a bio-weapon used by Pyrovores and the 2nd Edition version of the Gargoyle. A living flamethrower, the bile that the flamespurt disgorges burns on contact with the air and can reduce mot prey species to ash in moments.
* FlechetteStorm: Spinefists, one of the Tyranid's many SpikeShooter type weapons. [[DualWielding They are always wielded in pairs]], and [[BlowGun use compressed air built up from the wielding creature's own lungs]] to propel the spines. This means that the larger creatures with greater lung capacity can [[MoreDakka fire spines substantially quicker]].
* FragileSpeedster
** Hormagaunts are a Tyranid species meant to swamp the enemy in close combat, and to accomplish that they are bred to be very, very fast and agile. However, they are also quite frail, which is why the Tyranids [[ZergRush send them in great numbers at once]]...
** As Tyranids do not rely on conventional Grav-Tech to gain flight or have powerful engines, they instead have to resort to good ol' hollow bones and wings for their fliers. Thus, Gargoyles, Harpies and flying Warriors tend to have weaker armor than their ground-based counterparts, representing how fragile they can be. Tyrants subvert this somewhat, as they are able to project a psychic field around them that's just as durable as armor, making them {{Lightning Bruiser}}s as a result.
** Surprisingly averted with the massive Hierophant Biotitan. Its stalky legs and exposed bone structure look fragile, but the thing is shockingly fast and incredibly durable, enough that it can stand toe-to-toe with a ''Reaver Titan'' in combat.
* GiantEqualsInvincible: Or they might as well, as far as Tyranid [[{{Kaiju}} bio-titans]] are concerned. With [[DeflectorShields warp fields]], [[HealingFactor rapid regeneration]], and [[DeadlyGas neuro-toxic spore emissions]], it generally takes something like a [[HumongousMecha Titan]] to fell one of these gargantuan beasts.
* GiantFlyer: Harridans, which are giant flying insect dragons in a nutshell.
* GiantSpaceFleaFromNowhere: Is this in both metaphorical sense and a literal sense to the universe at large; where every single faction (barring the Necrons and Tau) have their origins connected deeply to the Chaos Gods, it's telling that the horde of alien space locusts not only have no connection to them, but can actually cause the gods to ''piss themselves in terror through their collective mental chattering''. While every other race run the risk of being attacked by Daemons when using psychic powers, Tyranids are completely immune to this (although the in-game mechanic remains unchanged, and is explained as a psychic feedback to the hive mind rather than a daemonic incursion).
* GoMadFromTheRevelation: Only one known character (Chief Librarian Tigurius of the Ultramarines) has actually made psychic contact with the HiveMind and ''not'' been rendered utterly insane immediately, or outright died from the psychic shock. He described it only as "an immortal hunger", spread across and uniting quadrillions of beings.
* GuiltFreeExterminationWar: With every other race in the setting. The Imperium and Eldar just want to survive, Chaos has a bone to pick with the Imperium, the Tau want the Greater Good, and Orks just want to have fun. Tyranids just want to consume, and while there have been desperate alliances between the races, there's no negotiation with the 'Nids. Kill or be consumed. The Allies matrix in the 6th and 7th edition rules allowed every other faction to form Alliances of Convenience with one other faction. Tyranids, in contrast, couldn't even form ''desperate alliances'' with anyone other than their Genestealer Cult minions. They're hated across the galaxy.
* HealingFactor: Rapid regeneration has been an upgrade for the larger Tyranid bioforms since the 2nd Edition of the game. How the rules represent this ability changes depending on the edition, with the 2nd Edition rules allowing the creature a chance to regenerate injuries whenever its Wounds characteristic has been reduced to 0, while 8th Edition has the "Rapid Regeneration" Stratagem that allows a Tyranid to regenerate a random number of wounds whenever it is used.
* TheHedgeOfThorns: Weaponized with the Barbed Strangler and its larger Stranglethorn Cannon cousin. It launches a dense seed organism, and whatever it hits gets quickly devoured for mass as it shoots out thorny vines in all directions, ripping apart the target and lacerating and snaring all around it. After a brief period its life is expended and it falls dormant, with anything surviving the initial burst wrapped in hard, brittle, sharp vines.
* HiveDrone: The bulk of the Tyranid forces consists of drones under the HiveMind's control and with animal-level intelligence at best. Averted by synapse creatures, which receive a greater degree of independence in order to control sections of the swarm or operate behind enemy lines.
* HiveMind: This is the Tyranids' most dangerous aspect; the entire race, at least from the Norn Queens through the synapse creatures, have a shared mind that is incredibly intelligent and has enormous psychic power. Chief Librarian Tigurius of the Ultramarines is the only human pysker who has made contact with it and survived (everyone else died or went insane), and could only describe it as "an immortal hunger."
** While the Hive Mind of the Tyranids is immensely intelligent and able to coordinate enormous actions across entire systems and subsectors with terrifying efficiency, it tends to have some limitations, at least on the strategic level. Hive Fleets seem to operate under general orders and objectives and are relatively inflexible in how they carry out those actions. Kryptmann essentially tricked an entire Hive Fleet into attacking in a controlled direction by capturing and using as bait several specimens of genestealers that were drawing the fleet forward. If a Hive Fleet is damaged enough that it can no longer form any sort of coherent force, then it will fall apart into splinter fleets whose sole purpose is to simply attack and consume inhabited worlds with no further strategic goal in mind.
* HiveQueen: Synapse creatures, though only the rarely seen Norn Queens are female. Probably.
* HollywoodTactics: Averted. They may 'look' like dumb animals, and use superior numbers, but the Hive Mind is a tactical and strategic super-genius.
* HordeOfAlienLocusts: After the invasion, they even "recycle" their own soldiers, living and dead.
* HorrifyingTheHorror: The Shadow in the Warp is so potent and terrifying it's been known to drive men as jaded and wicked as Chaos Sorcerers to insanity.
* HostileTerraforming: The effect [[AlienKudzu Tyranids have on planets they invade]], pre-consumption, involves some rather unpleasant alterations to the existing biosphere. This serves to "tenderize" the planet, making the biomass easier to process and consume when the hive fleet moves in after the defenses have been neutralized.
* HyperactiveMetabolism: If a Haruspex kills an enemy with its maw, it can regenerate a wound as soon as the Fight phase ends.
* ImprobableAimingSkills: The Hive Guard, a heavily armored feeder tendril guardian, wields an [[ImpaledWithExtremePrejudice Impaler Cannon]], a weapon which fires long spikes with membranous fletching at extreme velocity. The Hive Guard in fact [[EyelessFace has no eyes]], but "sees" through other members of the swarm, allowing it far greater situational awareness than it would otherwise have. Further, the spikes themselves possess a rudimentary awareness, flexing their fletching membranes in flight to adjust their trajectory and further ensure a target is hit, even from extreme range and in bad conditions.
* ItCanThink: The larger "synapse" Tyranid creatures certainly can. However, these creatures take more time and biomass to develop than the smaller ones, and thus there tend to be fewer of them, while the others must make do with more animalistic intelligence. However, as long as smaller creatures remain near the bigger ones, they can benefit from its intelligence thanks to their HiveMind.
* ItsRainingMen:
** Tyranids typically arrive on a planet's surface via "mycetic spores" dropped from space, especially the larger creatures which take more time to mature. Smaller ones are typically born "in the field" via the [[AlienKudzu consumption of the local environment]].
** Tyranid Gargoyles are variations on the gaunt genus with wings to carry them aloft. Their role is to [[DeathFromAbove swoop down on enemies from above]] and keep them occupied while larger creatures move into position. When Gargoyles have to move long distances, they will accompany a larger, [[OurDragonsAreDifferent dragon-like]] flier called a Harridan, clinging to its underside to save on their own energy.
* TheJuggernaut: This is the function of the Carnifex unit. It acts as a line breaker, plodding forward implacably as attacks waste themselves against its exceptionally dense carapace, cutting down or bowling over anything that stands in its path like a living battering-ram.
* KeystoneArmy: The [[HiveQueen synapse creatures]] are the ones with strong enough psychic reception to form a continuous connection to the HiveMind, while all the lesser creatures have to make due acting on crude instinct or being directed by nearby synapse creatures. As a result, targeting the synapse creatures can cause a Tyranid army's higher level tactical direction to fall apart, turning them into simple (if savage) beasts to mop up. However, this only lasts until other synapse creatures replace the fallen ones. A force defending against Tyranids needs to know when to press its advantage and when to fall back and hunker down against their otherwise [[ZergRush overwhelming numbers]].
* KrakenAndLeviathan: The bigger hive ships are this of the SpaceWhale variety. Also forms an [[AnimalThemeNaming animal]] and [[ReligiousAndMythologicalThemeNaming mythological]] ThemeNaming scheme for the hive fleets.
* LargeAndInCharge: Larger Tyranid organisms are more likely to be the synapse creatures directing the swarm, leading to the Imperium's official policy on combating them: shoot the big ones.
* LifeDrain: A Neurothrope allows its unit to heal lost wounds if they kill an enemy with the Smite psychic power.
* LivingGasbag: Tyranid spore mines are these, with jellyfish-like tentacles hanging below them and thin but rigid series of small overlapping chitinous plates surrounding its float-bladder. The Tyranids launch them from the biovore species to float over the battlefield and find targets. They tend to end up hovering just above the ground and have limited locomotion, but when a non-Tyranid draws near them [[ActionBomb they explode]], the sharp pieces of their shell scything out like shrapnel and spreading toxic spores and caustic fluid as they do so.
* LivingShip: The Hive Fleets, complete with [[WombLevel disturbingly fleshy interiors]].
* LivingWeapon:
** The Tyranid units themselves are these, as they are explicitly bred as living combat tools.
** To a more specific degree, the weapons used by smaller Tyranid units symbiotically bond with their wielders into a single organism.
* LongRangeFighter: The warrior lifeforms of Hive Fleet Kronos have been noted to wield a disproportionate number of ranged bio-weapons compared to other Hive Fleets. This adaption is due to Kronos' specialisation in combating daemons and other Chaotic forces that excel at close assault.
* MagicIsAMonsterMagnet: In ''Pharos'', misuse of the eponymous xenotech attracted the Tyranid to the Milky Way.
* MasterSwordsman: Hive Tyrants, of swords made out of razor-sharp-bone with a psychic brain at its base yes, but still [[MasterSwordsman swordsmen nevertheless]]. The Swarmlord cranks this up to absolutely ludicrous degrees, weilding ''four'' such swords at the same time, and so blindingly fast with them that a virtually impenetrable wall-of-blades is what your sword will clash into if you try to fight it hand-to-claw.
* MonstrousCannibalism:
** The Tyranids consume all lifeforms they come across, including their own {{Mooks}}, absorbing the biomass to create more warrior organisms for their next assault.
** Hive Fleet Hydra will intentionally seek out the remains and survivors of previous Hive Fleets that have been defeated, consuming their predecessors to fuel the Hive Fleet's infamously rapid reproductive abilities.
* MookMaker: Tyranid hive ships, for starters, making every smaller creature and even other hive ships themselves. Below that, Tyranids seed invaded worlds with brood nests, which consume the local resources brought to them and churn out smaller creatures on-site, allowing them to change their force composition in the field. Taking this one step further, some Tyranid creatures themselves are {{Mook Maker}}s themselves, such as the Tervigon, which spawns Termagants from various womb-pustules on its belly while on the battlefield.
* MoreTeethThanTheOsmondFamily: Though some critters mix things up with feeder tendrils.
* MotherOfAThousandYoung: Hive Ships are storehouses of all the genetic information needed to spawn every other Tyranid organism. While they might birth a few directly themselves, more often they birth the seeds which land on a planet with a rich biosphere and in turn birth more creatures as they consume the local environment.
* MultiArmedAndDangerous: All the Tyranids are evolutions from a basic six-limbed shape, and most use all of them, except for some like the serpentine Raveners and the winged Gargoyle who have a pair of vestigial legs.
* MyBrainIsBig: Zoanthropes have always had huge heads, the better to channel psychic power. Models from earlier editions had torsos, arms, and legs, and would stand and walk on the ground. ArtEvolution has pushed later models into being little ''besides'' a brain, with a long, snake-like body to house its brainstem. It now uses [[PowerFloats its psychic power to levitate]] over the battlefield, rather than walk.
* NamedAfterTheirPlanet: Since the Hive Fleets' true origin is a mystery, they are named after Tyran, the first Imperial world that they made contact with.
* NamesToRunAwayFromReallyFast:
** Not for nothing were the Tyranids nicknamed "the Great Devourer". Whole planets are left as completely lifeless rocks, stripped of any and all biomass and minerals that could be useful.
** The Swarmlord, Hive Tyrant, Tyrant Guard, Red Terror, Broodlord, Old One Eye, Death Leaper and the infamous Carnifex all get a special mention. Even names that don't have obvious meanings, like the Trygon, sound ominous.
* OnlyKnownByTheirNickname: This applies to the few special characters the Tyranids have (see below), because they don't have names or identities as humans do.
* OrganicTechnology: It's interesting looking back over the model range to see how what once were distinct weapons became fused to their wielders.
* OurDragonsAreDifferent: The Harridan, a giant flying Bio-Titan, is basically a dragon in space.
* OutsideContextProblem: Arguably one for the setting, even more so than Chaos. They're an extra-galactic threat, having already consumed other galaxies and now they want ours. They're also the only faction that is truly ''united'': countless trillions of organisms all devoted to infiltration, consumption, evolution, and migration. Power, glory, the favors of gods... absolutely meaningless to them. The Tyranids seek ''only'' to devour, and once they're done, they'll move on without even looking back.
* ProportionatelyPonderousParasites: Larger Tyranid organisms will often have smaller organisms attach to ([[MookMaker or birthed by]]) them, detaching to engage targets. The smallest of these are the AbnormalAmmo in the {{Living Weapon}}s wielded by other Tyranid creatures; the largest are other hive creatures which live aboard their {{Living Ship}}s. In between, you have things like Gargoyles clinging to Harridans for long flights, or other creatures which live on bio-titans.
* PlanetEater: They consume entire biospheres, leaving only an airless, infertile sphere of bedrock behind.
* PoisonousPerson: All Tyranids poison the environment as part and parcel of their invasion strategy. Hive Fleet Gorgon specializes in this, to the point of whipping up brews toxic enough to kill ''Plague Marines''.
* PowerFloats: Zoanthropes do not even have legs, they just hover along via psychic levitation.
* PsychicStatic: One of the most dangerous aspects of the Tyranids is how the Hive Mind casts a "shadow in the Warp" ahead of it, which is strong enough to [[YourHeadASplode overwhelm any psykers]] on a planet targeted by the Hive Fleets. This is very bad news, since psykers are required for astropathic communication and navigation, which means when the 'nids are on their way, there's no chance of sending a call for help, and no way for it to arrive. Some Imperial scholars believe that the cause of this is the absolutely ''massive'' amount of psychic "bandwidth" that the Hive Mind requires, simply drowning out all other psychic voices in the area. It's described as a million voices all chattering in unison.
* PuppeteerParasite: The Cortex Leech, a little-known ripper genus. It's a small, fast-moving creature which leaps up to a victim's face, then extends flexible antenna into the victim's [[OrificeInvasion mouth, nose, ears]], and {{eye|Scream}}s. These feelers burrow into the brain, and turn the victim into a drooling puppet of the HiveMind.
* {{Reincarnation}}:
** Hive Tyrants are unique in that they have distinct consciousnesses and personalities, which help them be more effective "generals." As part of the Hive Mind they can never be killed, meaning that if you destroy a Hive Tyrant in one battle, the next time you meet he'll remember your tricks, ''and'' he'll be pissed. The Swarmlord is believed to have involved in every major Tyranid conquest in their history in this way.
** The Swarmlord is a special character when compared to the other Hive Tyrants in the fact it is uniquely separate from the Hive Mind. Think of it as a very dangerous second opinion brought in only when the Hive Mind's usual strategies[[note]]'strategies' and not tactics, as the Tyranids constantly mutate and experiment to ensure tactical efficiency[[/note]] do not work on the foe it is currently fighting. What makes it unique is that while there are many Hive Tyrants, it's implied that there is only one Swarmlord at any given time, having its consciousness beamed across star systems on an as-needed basis. It's the sole Hive Tyrant that is not bound to any one hive fleet or ship.
* RentAZilla: Tyranid bio-titans, giant beasts which stay mobile via the hivemind's psychic strength both lifting them and protecting them with warp-shields.
* SandWorm: The Tyranids have something close in the Mawloc, a worm-like Tyranid with six powerful burrowing limbs alongside a long, chitin-plated serpentine body ending in a wicked earwig-like tail. Much like the classic trope inspiration, they are almost entirely blind and rely on sensation of vibration through the ground. Even a person standing stock still can be detected by a Mawloc, if their terrified heart is beating loud enough...
* ShockAndAwe: Tyranids of the Trygon genus produce a strong bio-electric charge, which the creatures use to wreath their claws with crackling power. The Trygon can also discharge this energy in a high-voltage bio-electrical pulse can reduce the enemy to a pile of charred bones. The more powerful Trygon Primes have even evolved various spines along their bodies that allow the beast to harness this electrical energy and unleash it with greater power.
* SpikesOfVillainy: Tyranid creatures are almost universally covered in chitinous spikes and sharp edges. As one Creator/GamesWorkshop player once said in a battle report:
--> You can talk all you want about strategy and unit choice, but [[WhenAllYouHaveIsAHammer when it comes down to it]], all Tyranid tactics end up as "spiky death".
* SpikeShooter: Stinger Salvos, Cluster Spines, Impaler Cannons...the Tyranids are not short of variations on these.
* StarScraper: Capillary towers are an ''organic'' version of these. As the ecological transformation of a Tyranid invasion begins to reach a "critical" stage, these begin to grow out of the accumulated biomass and rich minerals that the invasion has been rendering down into [[AcidPool digestion oceans]]. They gradually grow to a height of several kilometers, and act as anchor points for hive ships, who extend feeding tendrils down to latch onto them and draw up the rendered biomass through them, like drinking up the biosphere through a giant straw.
* SuperPrototype: The Tyranids' "Characters" in general are this rather than true individual characters, but it's entirely literal in the Doom of Malan'tai. The "mass-production" unit derived from its template (the Neurothrope) isn't quite as powerful as the prototype.
* SuperSenses: Many Tyranid bioforms have senses far sharper than those of their prey, able to discern the position of those they hunt with near supernatural accuracy. How this is represented in game changes depending on the edition but generally involve upgrades that confer bonuses to the creature’s Ballistic Skill or To Hit rolls.
* SuperSpit:
** When fighting in close combat, Gargoyles spit [[PoisonIsCorrosive corrosive venom]] into the face of their enemies in an attempt to blind them so that the fragile creatures have a greater chance of bringing down their opponent in melee.
** The Hive Crone’s main offensive weapon against ground targets is the Drool Cannon. This bio-weapon allows the flying monstrosity to vomit its highly-corrosive digestive juices onto its target, doing more damage than a [[FireBreathingWeapon heavy flamer]].
** Some Tyranid bioforms, such as the Screamer-Killer breed of Carnifex, are able to produce a ball of bio-plasma within their stomachs that the creature can vomit at their prey. Although relatively short ranged, these balls of plasmic vomit do a comparable level of damage to the [[PlasmaCannon plasma weaponry]] of other races.
** The saliva of a Pyrovore is highly acidic and is capable of reducing any organic or inorganic substance to a gelatinous slime that is easy for other Tyranid feeder organisms to consume.
* SuspiciouslySimilarSubstitute: The Tyrannocyte, introduced in 2015, is nearly identical to the older Mycetic Spore, a unit introduced in the 5th Edition Tyranid codex but were later removed in the 6th Edition codex in 2014.
* SuspiciouslyStealthyPredator: Lictors are the Tyranid's primary scouting units. They are able to stay perfectly still for days at a time, capable of changing their color to perfectly blend with the surrounding, and can alter their own body temperature to match the ambient level so as not to show up on infrared. Further, because they feed on the BrainFood of individuals in the area they are operating and gain some of that creature's knowledge by doing so, they know what things like security systems are and possibly where they are likely to be located as well. All this combines to make them creatures that are very hard to find if they do not wish to be found, and easily able to slip past even alert defenses.
* TheSwarm: The "ripper" genus is a family of many kinds of small Tyranid organisms which primarily exist to gather biomass for the swarm. They are weak and possess little offensive ability on their own, so they are typically only deployed after resistance has been cleared out to consume passive prey. Their quick-breeding allows them to multiply in numbers such that they form a rolling "wave" of living creatures that leave only desolation in their wake. A defender should hope that they were killed by one of the larger creatures as opposed to simply wounded [[EatenAlive by the time the rippers get to their body...]]
* TakingTheBullet: Serving the role of bodyguards for Hive Tyrants, Tyrant Guards can choose to intercept a hit aimed at the Tyrant and suffer a wound in its place.
* TakingYouWithMe: Most Tyranid monster-sized organisms (except Carnifexes, Maleceptors, Tervigons, Malanthropes and Dimachaerons) have the Death Throes special rule, which inflicts wounds on nearby enemies if the unit in question dies, representing the beast lashing out in its death throes before expiring.
* TentacleRope: Tyranid flesh-hooks are a variation of these, except instead of lashing around a foe, they ''dig a boney meat-hook into them''. They also function as a [[GrapplingHookPistol Grappling Hook Launcher]] for scaling obstructions.
* ThemeNaming:
** Many Tyranids are named after relatively obscure words for unpleasant and domineering women: harridan, termagant (and its older form, Tervigant, when it referred to a pagan god that medieval Christians believed Muslims worshiped), harpy, and dominatrix, though many of these are also puns or references--termagants were a type of ground unit from the 1970s Metagaming game ''Chitin: 1 The Harvest Wars'', and harpies are, of course, a type of mythological flying beast.
** The Hive Fleets, for the most part, have been named after mythological beasts and monsters. The three most major Hive Fleets to date have been Behemoth, Kraken, and Leviathan, and smaller Hive Fleets have included Jormungandr, Medusa, Scylla, and Tiamet. There are even two with literary names: [[Creator/HPLovecraft Dagon]] and [[Literature/{{Beowulf}} Grendel]].
* TooManyMouths: The Hive Mind thought it was a good idea to warp the Dimachaeron's thorax into a gigantic maw.
* TunnelKing:
** The Tyranid Ravener is a slithering creature capable of tunneling under the surface to bypass static defenses and literally undermine entrenched positions. For high value and seriously hardened targets, groups of Raveners will often be lead by a Trygon, their far-larger cousin.
** Now with even greater emphasis on tunneling comes the Mawloc. These things are like [[Film/{{Tremors}} Graboids]] turned UpToEleven.
* UnbreakableBones:
** Tyranid swords and other close combat weapons are made from hardened bone that is tougher than steel.
** In older editions, larger Tyranids (most notably Carnifexes) could have bonded exoskeletons, where the gaps between non-moving bones filled up with more of the same substance. The most notable area is the ribcage, where instead of a cage of bones, it turns into basically a sub-dermal shell. In-game this had the effect of raising the creature's toughness. Another upgrade, Extended Exoskeleton, works in a similar way but instead grows larger chitin plates on the creature's back, covering more vital areas and granting a higher Armor Save. Needless to say, both options were very popular until they got removed.
** The bio-forms of Hive Fleet Tiamet have the toughest exoskeleton of any Tyranid lifeform ever encountered. The diamond-hard carapaces of the Hive Fleet’s organisms allow them to survive firepower that would annihilate the lifeforms of other fleets.
* TheVirus: Or more precisely, The Bacterial Microbe. Several of the initial Mycetic Spores launched during a Tyranid invasion release these microbes around their point of impact. The microbes potentially infect nearby lifeforms, causing mutation, death, and rapid decomposition. This in turn grows into colonies of brood nests to birth more Tyranids, and jutting spore chimneys which spout more of these microbes into the air to let the wind carry them elsewhere. Eventually, [[AlienKudzu all native life is choked out by this process]] and the world becomes a wasteland of digestive pools and vein-like bio-mass capillaries.
* WalkingWasteland:
** The Venomthrope and Toxicrene Sporecaster Organisms constantly spew thick clouds of highly toxic, semi-sentient, microscopic spores that break down organic tissue at a prodigious rate. These spores are so deadly that they will infect everything in the surrounding area, tainting the soil and poisoning the atmosphere until the entire world is rendered uninhabitable. In the 8th Edition of the game this is represented by units and models in close proximity to a Venomthrope or Toxicrene having a 1 in 6 chance of suffering [[UnblockableAttack mortal wounds]].
** While all the warrior-forms of Hive Fleet Gorgon carry [[PoisonousPerson highly toxic spores within them]], the leader beasts of the swarm are surrounded by clouds of an even more potent strain of spore that chokes and infects all non-Tyranid life in the surrounding area. In the 8th Edition of the game this is represented by the Lethal Miasma Gorgon Warlord Trait that causes every enemy unit close to the Warlord a 50/50 chance of suffering a mortal wound.
* WeaponWieldsYou: The symbiotic [[PlasmaCannon bio-plasmic cannon]] is far more intelligent that the Exocrine weapon beast that it is bound to and is able to supress the simple mind of its host so that it can move itself into an optimal firing position.
* WeaponizedOffspring: When other Tyranic attacking forces have been devastated, Rippers have been observed to burrow into the ground and undergo spontaneous metamorphosis into a wide variety of other Tyranid genus. This leads some Imperial scholars to speculate that the Rippers are in fact an immature or larval form of Tyranid.
* WeHaveReserves: ... that outnumber the stars. Graphical representations of the hive fleets portray the overall force as being roughly as large as the ''Milky Way itself''.
* YouAreWhoYouEat: The Tyranid can make use of the genetic code of the worlds they consume. For instance, the Zoanthrope "Doom of Malan'tai" got its name and extra psychic power from eating a bunch of Eldar ''souls.''
* ZergRush: The most basic Tyranid battle plan is to overwhelm the enemy with floods of small fighting creatures like Termagants and Hormagaunts.

[[caption-width-right:350:Genestealers (behind) with a Genestealer Cult (foreground).]]

Vanguard organisms of the Hive Fleets, Genestealers are deployed well ahead of the fleet's advance to undermine potential prey worlds. Once a Genestealer arrives on a world, it will introduce its genetic material into portions of the populace. This drives them to breed and spread the infection, creating a cult of hybrids that slowly but surely undermines the world's social structure, military, and government while creating a psychic beacon that draws a Hive Fleet to the world to harvest its biomass.

Because of this mission, Genestealers are bred to be much more independent than the Hive Fleets, a Genestealer brood being almost a separate hive intelligence unto itself. Capable of hibernating in wait for centuries, Genestealers were likely by far the first Tyranid organisms in our galaxy, their numbers maintained and expanded via their parasitic preying on other species for reproduction. With great strength packed into a compact body and claws capable of rending through even the toughest armor, Genestealers are deadly whether they are acting subtle or overt.

Genestealers were have been a part of ''Warhammer 40,000'' since the 1st Edition of the game, where they were an alien race originally unrelated to the Tyranids, and have appeared in a number of [[GaidenGame spin-off games]] such as ''TabletopGame/SpaceHulk'' and ''Advanced Space Crusade''. Later lore made Genestealers a vanguard organism of the Tyranid Hive Fleets and they have been inseparable from the forces of the Great Devourer ever since. Genestealer Cults were initially introduced in ''TabletopGame/SpaceHulk'' before being introduced to the 1st Edition of ''Warhammer 40,000''. The Genestealer Cults were included as an appendix army list in the 2nd Edition ''Codex: Tyranids'' but, although they received a few unofficial and fan made army lists, they were relegated to a background-only faction until February 2016’s board game ''Deathwatch: Overkill'' saw them face off against the alien hunters of the Deathwatch. The Genestealer Cults were reintroduced into the core ''Warhammer 40,000'' game in October 2016 with the release of their first codex sourcebook and a full range of models. The rules for using Genestealer Cults in the 8th Edition of ''Warhammer 40,000'' are included in the ''Index: Xenos 2'' book released in June 2017 with additional rules released in the ''Chapter Approved 2017'' rules supplement.

* AbsurdlySharpClaws: Genestealer claws are Absurdly Sharp, even by the standards of the setting, and the muscles on their limbs are much more powerful than they look. Stories abound about Genestealers able to rip open the armor of a Space Marine Terminator like it was a tin can (though in practice the Genestealer can only do that if it gets a really lucky grip on the victim.)
* TheAgeless: Genestealer Patriarchs are known to live for hundreds of years, and unless killed, are practically immortal.
* AliensMadeThemDoIt: Literally in the case of those subjected to the [[FaceFullOfAlienWingWong Genestealer's Kiss]]. Their altered hormones will drive them to find a partner to mate with and produce offspring. Said offspring will incorporate the genetic code of the Genestealer who administered the kiss and will be [[MixAndMatchCritters horribly misshapen hybrids of the two species]].
* ApocalypseCult: The Genestealer cults, who prepare the planet for the Tyranid invasion. Their apocalypse involves the Tyranids devouring anything that offers resistance, then turning everything alive on the planet (including the Tyranid forces and surviving Genestealers) into soup so it can be absorbed by the hive fleet.
* ArtEvolution: When originally introduced, the Genestealer Patriarch looked like a big fat bastard sitting on his chair. With the revamped and revived Genestealer Cults in 2016, it now looks like a regular old Genestealer, albeit bigger and more robust.
* AssimilationPlot: The modus operandi of a Genestealer {{cult}}, though {{downplayed|Trope}} to the extent that they do not necessarily want to get ''everyone'' in. The early stages of a Genestealer population infiltration will have the brood lurk around the outskirts of society, careful to avoid detection and "[[FaceFullOfAlienWingWong kissing]]" a few lone individuals who will not be missed. As the cult adds new generations and grows in size, they will start fronts to allow them more freedom of movement and resources, becoming more selective as they go about who they bring into the "family" to groom themselves for more influence and avoid discovery. Eventually as a Hive Fleet approaches, they are driven to be more aggressive and will try to stage a coup, which may or may not be successful, but either way will divert attention and resources away from the oncoming threat.
* AwesomePersonnelCarrier: For what counts as a civilian vehicle, the Goliath Truck is packed with firepower and can tag along several Genestealer Cult members. It is like a beefed up Ork Trukk for just less than double the points, but with more armour and bigger guns.
* BaldOfEvil: Genestealer hybrids have a tendency toward baldness (as Genestealers themselves are hairless), though this may or [[DependingOnTheWriter may not be present]] depending on [[MixAndMatchCritters which traits are inherited from which parent species]].
* BreedingCult: The goal of Genestealer cults being to propagate more Genestealers in secret, gathering higher influence to better hide their growing numbers.
* TheBusCameBack: Genestealer cultists, introduced during the earliest days of the game, were removed as playable units in 4th edition. In February 2016 they were re-released as part of the board game ''Deathwatch: Overkill'', with an accompanying dataslate containing rules for the very specific Ghosar Quintus cult featured in the board game. The release of ''Codex: Genestealer Cults'' brought them back in full.
* CarFu: The Goliath Rockgrinder, a Goliath Truck with a Drilldozer Blade shoved up front, is designed to ram other vehicles into oblivion and hopefully turn enemy infantry into meaty chunks.
* CoDragons: In a Genestealer Cult, if the Magus is the chief psyker and manipulator of a Patriarch then the Primus is the Patriarch's warmaster and chief lieutenant. While the Magus' role is to corrupt, the Primus serves to lead the cult into war.
* CoolCar: The Genestealer Cult army from the 1st Edition of ''Warhammer 40,000'' included a gothic-styled limousine for the Cult leaders to ride in incognito. Although the Coven Limo hasn’t been a part of the game since then, many veteran Genestealer Cult players still hope for its return.
* {{Cult}}: When Genestealers infiltrate a population, they will go underground and look for isolated victims to "[[FaceFullOfAlienWingWong kiss]]". These individuals will reproduce [[HalfHumanHybrid Genestealer Hybrids]] and love them like their own. In order to maintain their "family" they will often find some kind of front or cover story to keep the nature of their children concealed. Such will usually adopt certain aspects of the host culture, twisting it around to center about the Genestealers, creating a secretive sect devoted to spreading their seed.
* DestinedBystander: The Genestealers were introduced early into the setting as a small piece of background lore. Once the Tyranids arrived, their role in the narrative was greatly expanded as being early elements of the Hive Fleet seeded into our galaxy. This was most likely a {{Revision}}, which involved a few minor {{Retcon}}s which relegated [[CharacterizationMarchesOn the original Genestealer conception]] with a minor offshoot of the race as a whole.
* DumbMuscle: Genestealer Aberrants are massively muscled creatures capable of wielding heavy weaponry with ease. Though dim-witted, their instinctive need to defend their brood makes them valuable assets to the cult.
* FaceFullOfAlienWingWong: Genestealers reproduce via the "Genestealer's Kiss", an injection of their genetic material into a target via a long, diamond-hard "tongue." [[DependingOnTheWriter Depending on which bit of fluff you read]], this is either via a literal, face-biting parody of a kiss, or a slightly less {{Squick}}y injection into the torso, under the ribcage. The Literature/CiaphasCain novels use the latter method.
* GhostShip: The Hive Fleets are fond of leaving first generation Genestealer broods on space hulks, where they will go dormant and wait. Eventually the space hulk will arrive in a populated system, or it will be investigated by explorers, and there the brood will find their hosts...
* HiveMind: Like the Hive Fleets, the Genestealers have a hive mind. This mind is generally independent of the Hive Fleet, and is specific to particular broods, which is necessary considering that they often operate far from any other Tyranid organism and thus need to better think for themselves. However, when the Hive Fleets are inevitably drawn to a location where Genestealers have been reproducing successfully, those Genestealers will begin to become affected by the Hive Mind of the fleet, and will be spurred into more overt and aggressive action against their host populations. By the time the Hive Fleet arrives, the Genestealer brood will have been mentally re-absorbed into the Hive Mind of the fleet and function as their elite shock troops when overcoming its defense.
* HypnoticEyes: A characteristic of Genestealers is an ability to pacify potential prey by maintaining eye contact and moving slowly, though [[DependingOnTheWriter the fluff varies on how much this is used]].
* ImprovisedWeapon: A few of the Genestealer Cults' weapons, including the Goliath Truck, are originally mining equipment appropriated for use in the battlefield.
* LotusEaterMachine: Genestealer Cultists, tragically, are not actually aware the Tyranids view them as useful but temporary tools that will be eaten once they have sabotaged their world's defenses. To them, they're the servants of an enlightened and angelic race that will bring salvation to the universe, and see all the Genestealer traits as angelic features. This lasts until the Hive Mind re-assimilates the Patriarch and Purii, at which point it is no longer efficient and the Cultists have just enough time to scream.
* MagicKnight: The Genestealer Patriarch, a [=ML1=] Psyker with access to Biomancy, Telepathy and Broodmind, also enjoys ripping out 4 [=S6=] attacks with Rending, Shred, and [=AP3=], and can buy familiars to add even more S4 attacks to the pile. His combination of psychic powers, beastly stats and access to Invisibility means he can go toe to toe with most characters.
* MixAndMatchCritters: Genestealer hybrids, particularly first-generation ones, will mix an equal amount of characteristics from the genestealer and the host species. Later generations will {{downplay|edTrope}} the Genestealer traits further with each generation, until around the fifth or sixth generation purestrain Genestealers are born to them.
* TheMole: Genestealer cults fill this role on a strategic level for the Tyranid Hive Fleets.
* MultiArmedAndDangerous: As per the other Tyranid creatures, Genestealers have six limbs. Two for standing upright, two for fine manipulation, and two as [[AbsurdlySharpClaws rending claws]].
* NonhumanHumanoidHybrid: Half any-sentient-species hybrid. Genestealers have a curious reproductive cycle, where only a few early broods are birthed directly by the Hive Fleets, and all later members of the brood are born to host species that the Genestealers prey on. After infecting a host organism, that organism will be driven to reproduce, but any such offspring will be half the host species and half Genestealer. Naturally, such a creature is usually very misshapen as it [[MixAndMatchCritters combines traits of both species freely]]. However, later generations of hybrids will look progressively more like the host species, until by about the fifth or six generation they are completely indistinguishable from them. The children of ''that'' generation will then be more "pure" Genestealers and the cycle begins again.
* OurVampiresAreDifferent: The first recorded contact with Genestealers came from the moons of the planet Ymgarl. Originally though to be native to there, it was only later revealed that they were a specific mutation of the wider Genestealer species and a vanguard of the Tyranids. Instead of the maw found on other Genestealers, they have lamprey-like feeder tendrils that they use to drain blood of victims. They are able to conceal themselves with limited [[VoluntaryShapeShifter shape-shifting]] abilities, but this requires them to feed often to maintain. Though their shape shifting is powerful, the Hive Fleets display no desire to re-absorb them, leading to speculation that the mutation might be unstable if assimilated back into the hive.
* ParanoiaFuel:
** {{Invoked|Trope}} by the Genestealers. Their infiltration of planets has the primary effect of destabilizing them militarily from within so they cannot effectively mount a defense, but secondarily by making it difficult for the planetary authorities to conclusively determine which individuals have been subverted by the Genestealers or not, continuing to make it difficult to mount a unified defense as the population and chain of command falls into a pattern of distrust and fear.
** Their 2016 playstyle invokes this, with many units having the ability to drop back into Ongoing Reserves and using the "Cult Ambush" rules to appear literally anywhere on a good dice roll. With many of them being armed with demo charges or incredibly powerful short ranged weapons, spamming this ability can induce the same paranoia in your opponent. In addition their Broodmind Psychic Discipline is also focused on playing mindgames with the enemy, from weakening the opponent to outright taking control of them (one of the powers is literally "Mind Control").
* ThePatriarch: The actual title of the first Genestealer to found a brood among a host species. As the brood of hybrids grow, the Patriarch will slowly grow progressively [[LargeAndInCharge larger and more physically powerful]]. By the time the forth generation of hybrids comes about and new Genestealers are being born, the Patriarch will be a massive beast. As every member of the brood is psychically connected with the Patriarch, the more the brood grows in number the more the Patriarch's psychic potential grows to accommodate them, eventually becoming a fantastically powerful psyker in its own right.
* PortentOfDoom: If a Genestealer cult has grown to the point of open insurrection, a Hive Fleet is not far away...
* PowerCreepPowerSeep: Possibly moreso than any other specific example in [=40K=], the power of a Broodlord as a psyker. In the fluff he's a supernatural powerhouse rivaling even the best Space Marine Librarians, as strong in the ways of the Warp as he is with his claws and muscles. On the tabletop he's one of the weakest psykers available to ''any'' faction (level one, with only one actual power he can use).
* PuppeteerParasite: The "[[FaceFullOfAlienWingWong Genestealer's Kiss]]" initially causes confusion and amnesia in the host organism, which renders them placid and can take several hours to resolve fully. However, after that time it brings the host under the thrall of the Genestealer brood, altering their hormones and perceptions so that they come to love the Genestealers and any children they have by them. Some puppets may not even realize that they are being influenced by an external intelligence.
* PutOnABus:
** The Ymgarl Genestealers became a "special character unit" in 5th edition's codex, but were removed in the 6th edition codex.
** The introduction of the Broodlord in 4th edition was supposed to make all-Genestealer armies a possibility. 5th edition instead made Broodlords into unit sergeants, once again making you unable to field pure-Genestealer armies. 6th and 7th edition has flipflopped on this, retaining the Broodlord as a unit commander but also releasing several independent formations that can be composed entirely of Genestealers, making it possible to field legal armies of them again (with the release of Shield of Baal, there is now a Genestealer that can take a Warlord trait, coming full circle again).
* RogueDrone: Somewhat downplayed, but not all Genestealers are as willing as other Tyranid morphs to be recycled into bio-matter, and many will flee infected planets just before the hive fleet arrives. In an odd twist, Ymgarl Genestealers are forced to be this against their will -- their shapeshifting abilities are too unstable for the HiveMind to want them back in its gene pool, so they are abandoned after their use is over. Despite this, they still want to rejoin the Hive Mind, so they keep rejoining the swarms, just to always be ejected later.
** Presumably, this is what's happening if the Patriarch fights against the Tyranids-he is, after all, a pure Genestealer himself, so by all rights he should just be letting himself be recycled after eating his share of biomass. If he's fighting to defend his cult, then something has gone very wrong for the Hive Fleet.
* SigilSpam: An early sign of a Cult is the distinct Tyranid "wyrm", a curled representation of a limbless Tyranid bioform that resembles an {{Ouroboros}}. Inquisitors are thankful that ''all'' Cults seem to have it as a sacred symbol, and they emblazon it on everything they own.
* SuspiciouslyStealthyPredator: Because Genestealers are actually [[ItCanThink as intelligent as most sentient species]], and are [[HiveMind psychically connected]] both to each other and to the members of the host species they prey on, they tend to have a pretty good idea of the technological means by which others might identify or track their presence. Since they exist to infiltrate and spread as widely as possible before they are detected, they tend to be very good at this.
* UnwittingPawn: Even if they don't know it, after their planet comes to the Hive Fleet's notice, the destiny of a Genestealer Cult is sealed, because all surviving members will become food like the rest of the planet.

[[folder: Notable Beasts]]
Although one would argue that a HiveMind race like the Tyranids shouldn't have special characters -- indeed, on a meta-level, this argument resulted in their lacking any in their fourth edition codex -- the Tyranids have always had unique units, beginning with the Red Terror and Old One Eye in third edition, then adding more in their fifth and sixth edition codexes.

!!The Red Terror
->''"Emperor knows what pit spawned the hideous apparition we came to know as the Red Terror. It first attacked the outer bastion and twenty-four men died before we drove it away with flamers. We never even found the bodies of Lieutenant Borales and Captain Lowe, just a trail of slime that led away from the command post and into the tunnels. It returned the following night, and the slaughter began anew, but this time we were ready for it… or so we thought."''
-->-- From ''Twenty Days in Hell, the Retreat from Devlan Primus''

A blood-red Ravener-like monster that was responsible for terrorizing the Imperial miners of Devlan Prime for 20 days and nights, burrowing through the solid rockcrete with its six curving blade-limbs and devouring victims whole before vanishing once more. The Imperium has no idea what happened to it after that sighting.

* TheBusCameBack: The Red Terror was restored as a playable character in the 6th edition codex.
* LegacyCharacter: On a meta-level. Raveners gained their ability to Deep Strike -- flavored in-game as them burrowing up from below to attack their foes -- and Trygons and Mawlocs gained their existence from this creature, who was originally the only one who could do it. Perhaps in homage, his entry in the 2014 codex notes that some Imperial scholars have suggested that the Red Terror may actually have been the first ever documented sighting of a Trygon and/or Mawloc.
* ParanoiaFuel: InUniverse. What ''was'' the Red Terror? And what happened to it after Devlan Prime? Was it destroyed? Was it reassimilated and used to churn out the Trygons and/or Mawlocs? Or is it still out there, killing, and the Imperium doesn't know about it because nobody else has ever survived an encounter with it?
* PutOnABus: The Red Terror was removed as a playable model in the 4th edition codex, under the logic that a HiveMind race shouldn't have special characters.
* SwallowedWhole: Has the ability to do this, both in the background text and on the tabletop.

!!Old One Eye

A monstrous Carnifex that spearheaded the Tyranid assault on Calth, with the aid of its at-the-time unique healing abilities and bioweapons, only to be brought down by some brave Imperial hero, who seemingly killed it with a direct hit from a plasma pistol to the eye. Decades later, a band of smugglers found its frozen corpse and dug it out, hoping to sell it and be rich, only for the Carnifex to regenerate its wounds and resume to stalking the battlefields, somehow escaping Calth to bring death to the rest of the galaxy.

* AxCrazy: Even by Carnifex standards, Old One Eye is a frothing mad berserker.
* ArtEvolution: Old One Eye had its own variant of the 3rd edition "Grinfex" model, complete with unique body, arm and leg sculpts (in fact the only piece it shared with the stock Carnifex was the scything talons). This held through 5th edition, but 6th edition instead redesignated the current Carnifex kit as Old One Eye. This is notable because the kit was never designed to be Old One Eye in the first place, but had a head that represented him perfectly (a standard Carnifex head missing a portion of its face, revealing the skull). This change was because Old One Eye's original model no longer looked like the current Carnifex, and because GW has been phasing out older resin/metal kits and the current plastic kit was a dead ringer for him anyways.
* TheBusCameBack: It was restored as a playable character in the 5th edition codex and has been playable since.
* EyeScream: Got shot in the ''eye'' with a ''plasma pistol''.
* GiantEnemyCrab: Kind of invokes this image, thanks to its crab-like pincered limbs.
* HealingFactor: Infamous for it, InUniverse. In the third edition codex, it was the only Tyranid that could regenerate, whilst when it reappeared in the fifth edition codex, it had a version that worked more effectively than those of other Tyranids with the Regeneration biomorph, though it lost this in the 2014 codex.
* LegacyCharacter: On a meta-level. Old One Eye's ability to regenerate and its unique crab-like crushing claws became standardly available biomorphs in all subsequent editions.
* PutOnABus: Old One Eye was removed as a playable model in the 4th edition codex, under the logic that a HiveMind race shouldn't have special characters.
* WoundThatWillNotHeal: The empty eye-socket and exposed skull-patch from its first "death" is seemingly the only thing it can't regenerate.

!!The Swarmlord

The closest thing that the Swarm has to a true face, the Swarmlord is an ancient and incredibly powerful Hive Tyrant that is brought into being whenever the Hive Mind requires a greater level of tactical wealth and raw leadership than an ordinary Hive Tyrant can provide. If the Swarmlord dies, it is simply reincarnated again, and in this way it can be summoned to the aid of any hivefleet that ever needs its aid.

* CoolSword: Four unique serrated blades of organic bone/chitin sculpted around living crystals from outside of our galaxy.
* DualWielding: Taken UpToEleven in that the Swarmlord ''quadwields'' its bone-sabers.
* HiveQueen: Zigzagged. It does have a greater level of individuality than any normal Tyranid, and it is created when the Tyranids need more direct control, knowledge and purpose than the Hive Mind can give. However, it is still merely an aspect of the Hive Mind, not the actual leader of the Tyranid race, and so killing it does nothing more than killing any other synapse creature.
* TheLeader: Or at least, the closest to the concept that we can understand.
* MagicKnight: A powerful psyker and also very capable of curbstomping just about anything that gets into melee with it.
* NeverFoundTheBody: After the destruction of Hive Fleet Behemoth at the Battle of Macragge, the Swarmlord's body was never located. It's appeared on several battlefields afterwards, but it's unknown if it was killed and reincarnated, or simply managed to escape.
* ResurrectiveImmortality: The Swarmlord can be killed, but its mind is just absorbed back into the Hive Mind, which can then recreate it whenever and wherever it is needed.

!!The Doom of Malan'tai

The Doom was a mutant Zoanthrope who was instrumental in the destruction of the Eldar Craftworld Malan'tai, by sneaking into the Infinity Circuit and devouring the spirits of the deceased Eldar trapped within. Its fate after that battle is unknown.

* DegradedBoss: After the Doom of Malan'tai was removed from the 6th edition Tyranid codex, in November 2014 it was replaced by the Neurothrope, its 'uncountable progeny', which is a generic squad leader for Zoanthropes.
* DemotedToExtra: Although no longer a playable model, the Doom has an entry in the Zoanthrope info page in the 6th edition codex.
* LifeDrain: In the fluff, the Doom did this to the souls in Malan'tai's Infinity Circuit. In-game, the Doom did this through its Spirit Leech rule, which was known to wipe out entire squads to give the Doom a ton of health back. The Neurothrope has a less-potent version of this ability.
* LegacyCharacter: Much like Old One Eye and the Carnifex, it has been removed from the current edition and its ability instead appears on the Neurothrope upgrade for the Zoanthropes.
* PutOnABus: For legal reasons, the Doom was removed as a playable model in the 6th edition codex.
* YourSoulIsMine: Invoked in spirit, if not in word, by the Doom's assault on Malan'tai.

->''"It’s there, I know it is, lurking in the shadows, stalking me like an animal. It’s death itself I tell you, just watching me, waiting… Oh blessed Emperor, why won’t it just kill me?"''
-->-- The ravings of '''Cardinal Salem'''

The Hive Mind's ultimate assassin and psychological weapon, Deathleaper was first encountered on the missionary world of St. Caspalen where its campaign of terror so utterly destroyed the morale of the world’s defenders that they could barely put up much of a fight once Hive Fleet Leviathan invaded. Since the consumption of St. Caspalen, Lictors matching Deathleaper's appearance have been encountered alongside the vanguard organisms of a number of different hive fleets.

* ChameleonCamouflage: Deathleaper has the most advanced chameleonic skin of any Tyranid organism, able to blend almost perfectly into its surrounding. How this is represented in-game varies depending on the edition but generally make Deathleaper more difficult to hit with ranged attacks.
* ParanoiaFuel: InUniverse, this is its function.

!!The Parasite of Mortrex

A grotesque flying abomination first seen on Mortrex, an Imperial fortress-world in the Ultima Segmentum, the Parasite earned its name and its legendary reputation for its ability to implant Ripper eggs into its victims, causing them to be devoured from the inside out by rapidly-hatching swarms. Within two weeks of its appearance, it had overrun the entire planet with vast tides of ravenous Ripper Swarms. It has not been seen since, but the Imperial Guard are certain it's out there, somewhere...

* DemotedToExtra: Although no longer a playable model, the Parasite has an entry in the 6th edition codex.
* BewareMyStingerTail: It used its barbed ovipositor to implant Ripper eggs into its victims.
* FaceFullOfAlienWingWong: Can inject larval Rippers into victims through its tail-stinger.
* MookMaker: Those killed by its Implant attack create new bases of Ripper Swarms.
* PutOnABus: For legal reasons, the Parasite was removed as a playable model in the 6th edition codex.


[[folder: Zoats]]

A little known and largely forgotten piece of early Tyranid lore, the Zoats were a centaur-like slave race engineered by the Tyranids. In first edition days, nearly half a Tyranid force had to be made out of Zoats. They were never popular, and never made the transition to the next edition, only having a few references to them be dropped in the background of the third edition. Much like the Squats, they are something considered to have been dropped from the franchise.

* ChuckCunninghamSyndrome: Quietly dropped when the second edition was released. Details about their removal went unremarked until a footnote in the third edition explained their fate: being consumed by the Hive Fleets as they have [[YouHaveOutlivedYourUsefulness outlived their usefulness]].
* ContinuityNod:
** Though they haven't been brought BackFromTheDead, many fans think that the design of the Tyranid Hive Guard was a bit of a nod to the Zoats.
** Hive Fleet Colossus, given a few references in various rulebooks, is described as having centaur-like organisms, conch-like hiveships, painfully grafted symbiotic weapon organisms, technological weaponry absorbed and incorporated from other races it has overrun, and the ability to telepathically community with each other and with other races. Though not explicitly called Zoats, the description fits, and [[http://web.archive.org/web/20080411104249/uk.games-workshop.com/tyranids/forgotten-fleets/6/ Games Workshop's own (old) conversion guide]] makes it pretty clear that is what they represent.
* DroppedABridgeOnHim: The revamped lore indicated that the Tyranids created them as a semi-independent group to go ahead of the Hive Fleets as vanguards and disrupt targets for consumption. But being independent, they TurnedAgainstTheirMasters. However, finding themselves trapped between a rock and a Hive Fleet, they were quickly wiped out as the Hive Fleets caught up to them. The few who survived were spotted in Tyranid swarms, but their numbers dwindled as the Hive Fleets evolved to no longer need them.
* EarlyInstallmentWeirdness: They never made it past the first edition, as the [[CharacterizationMarchesOn March of Characterization]] from the Tyranids made them incompatible.
* GasMaskMooks: Zoats could only breath in very specific atmospheric conditions, and thus when not in a controlled environment like their ships they would each wear rebreathers.
* MouthOfSauron: The Zoats were to be harbingers of the Hive Fleet, letting others know that the Tyranids were coming for them, encouraging prey planets to surrender to the inevitable. [[CharacterizationMarchesOn This did not last long]].
* OrganicTechnology: They used much of it, though to a less animated extent than the Hive Fleets. For example, their ships were organic, but not {{Living Ship}}s, having their hull grown like a shell, then hollowed out and having more conventional technology built into it. Their ability to freely combine both organic technology and conventional technology allowed the Tyranid forces to employ things like bolters and missile launchers, in addition to their more usual fare.
* OurCentaursAreDifferent: They are lizard-like slaves to a HordeOfAlienLocusts.
* ServantRace: For the Tyranids.
* YouHaveOutlivedYourUsefulness: The justification given for why the Hive Fleets phased them out.

->''We cannot live through this. Mankind cannot live through this. In a single day they have covered the surface of this planet with a flood of living blades and needle-fanged mouths. Kill one and ten take its place. If they are truly without number then our race is doomed to a violent death before every shred of our civilization is scoured away by a force more voracious than the fires of hell themselves! Death! By the Machine God, Death is here!''