Bizarre Alien Biology



""Muahahahahahaha! Inferior human organs! ...Ow, my squeedlyspooch!""

- Zim, Invader Zim

Extra-terrestrials are weird. Sometimes, really weird. They may look relatively normal or mind-bendingly freakish, but whatever their appearance, you can bet that they don't work like us. They may have green blood or six sexes or any of a variety of other features that make it clear: these are alien!

Science Fiction at the hard end of the Mohs Scale of Science Fiction Hardness is more likely to feature really bizarre examples of Bizarre Alien Biology, though the soft end can get pretty weird at times too, especially when the Rule of Cool or Rule of Funny is in play.

May turn up during an Alien Autopsy.

Compare Anatomy Tropes.


 * Human Aliens
 * Humanoid Aliens
 * Rubber Forehead Aliens
 * Little Green Men
 * Alien Animals
 * Intelligent Gerbil
 * Fish People
 * Insectoid Aliens
 * Bee People
 * Plant Aliens
 * Blob Monster
 * Silicon-Based Life
 * Starfish Aliens
 * Energy Beings


 * Alien Blood
 * Alien Catnip
 * Alien Kudzu
 * Alien Lunch
 * Beware My Stinger Tail
 * Bizarre Alien Locomotion
 * Bizarre Alien Reproduction
 * Bizarre Alien Senses
 * Bizarre Sexual Dimorphism
 * Chest Burster
 * Evolutionary Retcon
 * Exotic Equipment
 * Extra Eyes
 * Eye Beams
 * Eyeless Face
 * Face Full of Alien Wing-Wong
 * Fartillery
 * Feather Flechettes
 * Heart Light
 * Hive Mind
 * Human Outside, Alien Inside
 * Kill It with Water
 * Living Ship
 * Mirror Chemistry
 * Multipurpose Tongue
 * My Brain Is Big
 * Nested Mouths
 * Non-Mammal Mammaries
 * Nuclear Nasty
 * Oculothorax
 * Puppeteer Parasite
 * Solid Gold Poop
 * Spare Body Parts
 * The Symbiote
 * Too Many Mouths
 * Translator Microbes
 * Vertebrate with Extra Limbs
 * Weird Beard

Anime and Manga

 * From Dragonball Z, we have several different types of aliens, the most normal being the Saiyans...who are insanely aggressive and love to fight, have tails, and can transform into giant apes in the light of the full moon if they still have their tails. Not to mention if they are put close to death and recover, they increase in strength exponentially. Despite this, they can interbreed with humans. Then there is Piccolo's race, the Namekians. They're apparently modeled after slugs, and on their arms their muscles are visible. And of course, they're green in color. But don't expect green skinned space babes...there's only one Namekian gender. Male. And they reproduce by spitting out eggs. Then there's Frieza's race. They can survive the vacuum of space and are so powerful, they have to revert to weaker forms so they don't end up destroying their surroundings. And they are insanely durable...Frieza for instance could survive being bisected, his eye eaten by the explosion of Namek, and come back as a cyborg. Finally, Humans of all races are bizarre to the rest of the galaxy since they can suppress and control their ki.

Film

 * From the Alien series, the Xenomorphs have the following quirks:
 * They have a second jaw inside their mouth, complete with its own working mouth, which can launch out hydraulically.
 * They are apparently Silicon-Based Life instead of carbon-based.
 * Their Alien Blood is yellow and highly acidic—enough to melt through nets and chains created by the Predators in the first AVP movie.
 * Most importantly is their reproduction style. Leaving the whole chestburster thing aside, Xenomorph DNA merges with the host's DNA to produce unique hybrids. For instance, there's a dog hybrid in Alien 3, and of course the infamous Predalien from AVP: Requiem.
 * The Xenomorphs' longtime foes, the Yautja, from the Predator series, have their own weird biology. Most notably, the "dreadlocks" they wear don't appear to be hair at all. Prop skulls from Predators show large sockets for the tendrils.
 * Expanded Universe material suggests that the dreadlocks are in fact hair, melted together into tendrils in an incredibly painful right of passage. Of course the Yautja are still bizarre, what with their glowing yellow-green blood and eyes that register heat rather than visible light.
 * On Men in Black, half the humor and plot points are drawn from the biological characteristics of the aliens they encounter, and K's encyclopaedic knowledge thereof. No matter how weird they look, almost all of them find ways to pass for a human. Or, in one case, a small dog. Or, in one novelized case, potted trees. Of course, the MIB refuse access to Earth to anything that cannot blend in with Humanity.
 * The second movie had a subway-train-sized alien worm with a tiny flower on its head hiding just beneath the surface, disguised as a weed.
 * In Avatar, most animals on Pandora breathe through spiracles in their chests rather than nostrils and possess six limbs or appendages.

Literature

 * In Larry Niven's Known Space series, the Pierson's Puppeteers have three legs ending in hooves, two heads that "resemble Cecil the Seasick Sea Serpent puppets" and double as hands, and have their brains in the middle of their torso.
 * The Sector General series lives by this trope. It's a hospital that caters to the most outlandish cases in the galaxy, treating aliens of all shapes and sizes. Really' all shapes and sizes; Rubber Forehead Aliens is completely averted in favour of whatever the author mind could conceive. The effects budget is not an issue in novels.
 * The Star Wars Expanded Universe often describes the unusual biology of aliens. In the films, the details of a species are rarely gone into in any depth.
 * Tbe Codru-Ji starts life a dog-like creature with 6 legs the size of a Doberman. As adults, they look like normal humans, only with 4 arms. No fur or otherwise canine features remain.
 * Banthas. Seriously.
 * Piers Anthony's Cluster series has numerous biologically bizarre aliens, including a water-squirting ball that lives off atmospheric gasses, magnetically-levitating disks of metallic particles that communicate by laser, a teardrop-shaped being with a single tentacle who rolls on a track-ball instead of legs (said ball also serving as the egg for females) and tastes the ground as it rolls, and sentient slime-fish with three sexes.
 * The Xsarn of the Gamester Wars trilogy resemble tentacled insects who form a seasonal hundred-person "mating ball" to reproduce (I've never been to one of those kinds of parties...) and eat feces. Since other species' wastes contain little food energy, they must eat almost constantly, and so Xsarn tend to carry feeding troughs with them everywhere. Making it worse, they tend to regurgitate when they get overexcited (which happens a lot). And You Do NOT Want to Know what their greeting ritual is like...
 * In Vonda McIntyre's Dreamsnake, the titular creatures superficially resemble ordinary small snakes, and are most notable for the use of their venom as a narcotic and painkiller. Unfortunately, they're rare and difficult to breed in captivity.
 * In the "Shatnerverse" series of Star Trek novels, where Kirk is resurrected after his death in Generations and goes on to live in the 24th century, the main characters encounter a super-secret group of Starfleet black-ops scientists with some pretty wongo ships. Several crewmembers are fully holographic, for example. The captain of the lead ship, a woman named Raddison, has a holodeck for a ready-room, and she appears in a different form with her room set to a different natural disaster recreation to different characters; a small Chinese woman to Kirk, a striking blonde to Riker, etc. In the end, Kirk asks her to at least tell him, among all of her secrets, which of her forms is the real one. She smiles and says, although using a plot reference instead of these words, that he's short-sighted for assuming all species are bipedal. Kirk, at this point, realizes that no matter what her holodeck ready-room looks like, there is always one single constant in the room that never changes. Captain Raddison is the room's potted plant.
 * From the mainstream Star Trek Novel Verse:
 * Syrath are crystalline life-forms who can regenerate themselves from only small pieces due to non-centralized anatomy, making them effectively immortal, if subject to personality change depending on how much original material is retained.
 * Frunalians undergo a metamorphosis during their adult life in which their exoskeleton falls off, their biochemistry (and personality) change and a fleshy mane-like sensory organ erupts down their backs. Frunalians know this change as "the Shift".
 * Pacifican Selkies also undergo a metamorphosis, from amphibious breeder to fully aquatic adult; again, part way through their adult lives.
 * Seleneans are able to link their brains together through specialized spines that permit them to alter each others' brain chemistry as a means of communication.
 * Several of the species featured in Star Trek: Ex Machina, whose physiologies and cultures are expanded from background material associated with Star Trek: The Motion Picture. These include the balleen-feeder Megarites, who require "drysuits" when out of water, and survive on nutrient injections where they can't filter-feed. Then there's the Zaranites, who rely on fluorine-dependent micro-organisms as part of their respiration.
 * In Animorphs, Hork-Bajir have two hearts and can survive being shot in one, Andalites have no mouths and absorb nutrients through their hooves and Yeerk reproduction involves three, none of which survive.
 * That's nothing compared to the Skrit Na, two species in one. A Skrit is basically a giant, fairly stupid cockroach, which at some point spins itself a cocoon and apparently dies. However, out of its dead body comes a Na, a smarter (but still weird) creature which is basically a member of The Greys.
 * In the Cthulhu Mythos Mi-go look like crustaceans with batlike wings and a fleshy orb covered with small tentacles in place of a head, but biologically they are closer to fungi (and they're not really fungi eighter. It's just what they resemble the most from Earth organisms). The Elder Things are described as being something akin to a mix of vegetable and crinoid. And lets not even go to the Great Old Ones which are not really made out of matter in the strictest sense of the word.
 * The entire landscape in The Stormlight Archive is like this. Probably has something to do with the massive highstorms coming every couple days. Most of the plants and animals look like things you'd find underwater. Extra bonus goes to the Parshendi, who are humanoid but literally grow their own armour (as in, it's a part of them), which weirds out people in-story.
 * The Demonocles in Rumo and His Miraculous Adventures have incredibly complex tongues.
 * One of the recurring themes of Keith Laumer's Retief series was bizarre alien biology that didn't fit the preconceived notions of the Obstructive Bureaucrats in the diplomatic corps, leading to horrible snafus that only Retief could sort out.
 * The kif from C. J. Cherryh's Chanur Novels have two sets of jaws, one at the front of their mouths and one at the back. The front set of jaws is used to rip flesh off of still-living prey, while the second set chews the meat into a paste before swallowing it (the throat of a kif is so narrow that it's incapable of swallowing anything solid). Further, the kif are carnivores who can only eat fresh meat, where "fresh" means "could be used in organ/muscle transplant operations". Meat that most other species of carnivores would consider fresh will make kif so nauseous that even when starving to death they'll be unable to eat it.
 * The t'ca (giant methane-breathing snake-worms) give birth if subjected to enough psychological stress.
 * In one of the Monk books, a convention for a Star Trek Expy are in town. The Spock Expy is an alien with pointed ears, a trunk, and three mouths.
 * Comes up in, of all places, The Chronicles of Narnia, when it is mentioned that centaurs have the stomach of a man and the stomach of a horse, and both appetites are very large, so a centaur's breakfast begins at sunrise and lasts until mid-to-late morning. (if looking for a specific reference, this is close to the end of The Silver Chair, after escaping the underground realm)
 * The Cheela from Dragons Egg are a pretty extreme example: living on a neutron star, they're not even made of atoms, but rather of tightly-packed atomic nuclei. Their body "chemistry" being based on nuclear reactions—millions of times faster than normal chemical reactions—they live and think much faster than humans, which is central to the plot. The fact they're also half-Plant Aliens and Blob Monsters that can create and dissolve their bones at will is just the icing on the cake.
 * Clifford Simak was prolific at creating imaginative aliens, often at least three or four new ones in each novel or story. Just in Project Pope, there were Dusters (sentient clouds of dust) and Spheres (spherical aliens that had to make themselves beat like a drum to talk to humans) amongst quite a few others.
 * "The Twerlik" from Jack Sharkey's eponymous short story is a huge, intelligent molecule. Its intelligence massively increases when it is unexpectedly given something to think about, in the form of a large input of energy from a visiting rocket's exhaust. As a result it learns to move, manipulate matter, read human minds and show gratitude - after a fashion.

Live-Action TV

 * Star Trek has a few examples beyond its usual Human Alien and Rubber Forehead Alien groups, like the Trill, who are (two or) three species with separate degrees of this. The Trill symbionts are alien slugs that live for millennia, and can bond with humans or humanoid aliens.
 * A Starfleet officer on DS9 named Vilix'pran (whose species has not been shown on screen) "budded" many children. Who had wings that had to be kept from tangling. Oh right, Vilix'pran takes the pronoun "he".
 * The freaking Ocampa. Lifespan of nine years. Body temperature around 16 degrees Celsius. Can only have one child. When ready to mate, they exude a yellow substance from their hands and must have an hour long foot massage with 50 hours of the substance appearing to enable mating. Give birth standing up, from a sack between their shoulders. While their psychic powers probably helped, one still wonders how a species with such bizarre, not to mention mathematically troublesome, method of reproduction could have come about in the first place.
 * Just to be fair, it was never said that Ocampa can only have one child, just that if they DON'T breed when the first opportunity comes up, they never will.
 * In the episode of Angel where Fred, she and Wesley spend the first couple of minutes fighting some small gremlin-like monsters, then discussing the creatures' biology. She describes a portion of their reproductive process, which evidently involves crystals, bacteria, and parasitism.
 * Farscape is, unusually for a TV series, full of truly bizarre aliens (as well as having the usual complement of humanoid and Rubber Forehead Aliens).
 * Hynerians fart helium when nervous.
 * Luxans can survive in a vacuum for a time, and their blood is clear when healthy and cloudy when ill or injured. And there's their tongues, which are longer than the rest of their body, and contains a spectrum sedative capable of knocking out almost any living creature it touches.
 * Then there's the fact that Scarrans don't have external sexual organs, which Chiana discovers after collapsing in agony from trying to knee one in the mivonks.
 * Pilot, and other members of the species known as "pilots", are adapted to be able to physically link with and communicate with the intelligent starships, to the point where removing them is dangerous.
 * The intelligent starships themselves, like Moya, are adapted to work with the pilot species, and, in general, to have human-like creatures living inside themselves. The degree to which the DRDs (repair 'bots) inside Moya are biological and part of her, vs. being mechanical and independent, is somewhat unclear as well.
 * It'd probably be quicker to give a list of aliens on that show who don't have Bizarre Alien Biology.
 * Humans. Good night.
 * The TV version of Alien Nation uses this a LOT. EVERY FRACKING EPISODE introduces some new and strange bit of Newcomer biology (including a whole arc about their strange reproductive process).

Myth

 * The excreta of the bonnacon, a bovine creature of Greek myth, caught fire upon contact with air; the beasts used that particular quirk in their anatomy as a weapon. And there's of course the hydra with its quite impressive regenerative physiology in regard the decapitations... And that's just the tip of the iceberg.

Tabletop Games

 * Dungeons & Dragons. Let's just say almost all non-humanoid creatures could be featured here, and half of humanoid ones. Sometimes combined with No Biochemical Barriers, and sometimes you have a goat-sized bug who feeds itself by rusting metal with its antennae.
 * Warhammer 40,000
 * The Orks in are said to be a mix between flesh and blood beings and fungus. Upon their death they release spores that in turn give birth to Orks and other creatures linked to them (Snotlings and squigs, for instance). Another very alien part in their biology is that ork-species never stop growing. If they get wounded and are allowed to heal, they grow even faster. Normally living organisms have a genetic limit on how big they can be, or they are limited by the environment where they live, but orks and their sub-species can grow infinitely.
 * Slaught are composed of worms. Lots of worms.
 * Cryptos are greenish gas clouds who can possess people and have limited mind control.
 * And then there's wildlife.
 * Nightwing is a critter native to Dusk, shaped like a slug with wings, that attaches and drinks blood like a leech... after it incapacitates the victim with narcotic dust.
 * Void-fluke is sort of vacuum-capable eel who in the wild eat asteroid ores, but they aren't too picky to gnaw on refined metals - like, say, someone's void suit - and became vermin spreading via ships over many systems.

Video Games

 * The Necromorphs are Hive Mind obeying alien bacteria that reanimate corpses into various Body Horror Demonic Spiders. Destroying the head doesn't slow them down, and unloading ammo into their torso doesn't either. Only hacking off their limbs, tentacles and yellow tumor-like growths stops them from turning you into food or another corpse to reanimate.
 * They can even convert dead body parts. Say you have a chopped-off finger that gets infected by the necrovirus: It'll sprout tentacles and spines and attack you.
 * Dead Space's Necromorphs are basically The Thing In Space. Though less paranoia about who is one, and more paranoia about when one is gonna pop out of air vent and tear you a few superfluous holes.
 * Star Control aliens include anything from Blue-Skinned Space Babes to living crystals crackling with electrical discharges and innate hyperspace communication capability, to Eldritch Abomination Hive Mind chatting in Starfish Language.
 * While most of the aliens in Deadlock are pretty standard Space Opera, the Uva Mosk (think a three-way cross between a shrub, a human, and either an anteater or a turnip) definitely fall into this category.
 * Zerg from StarCraft. Their organ tissues randomly mutate (and, in certain cases, steal new DNA from a new prey creature), and their hyperpowered immune system hunts it down, invoking "survival of the fittest, nature red in tooth and claw" on the genetic level. This allows a piece of formerly dead and rotten Zerg tissue cultured in a laborotory to un-decompose, and evolve 1000,000 times more than humans ever have in the space of a week. Their alpha amino acids have unique "R groups" that allow damaged cells to fuse with protein to repair themselves. It also allows them to ignore Biochemical Barriers by adapting to be compatible with host organisms. They can reproduce through parasitic fusion, or larvae produced from a building that eats mineral crystals, drinks liquid vespene gas, and is built around six wombs (complete with birth canals), a brain, and a stomach. Their buildings are really self-contained organisms that are based on the genetically programmed nest site architecture of their prey species, and one building is specifically designed to do that ultra-evolution thing at an accelerated rate. They don't need to breathe, and their flesh is dense enough to count as a spacesuit. Their metabolism is so fast that, on top of meat, they eat minerals and drink vespene (which is a mutagen, so that helps things along considerably). The downside to this is that they are very susceptable to radiation poisoning.
 * The Protoss are relatively normal biologically in comparison, but that's not saying much in light of the above. They've got digitigrade legs, and No Mouth, which they make up for by being photosynthetic and able to absorb water vapor through the skin. Also, with a bit of training, they can turn pure rage into Wrist Blades and cut you to pieces. With a bit more training, it's either invisibility or climate-altering Psychic Storms.
 * In Metroid, Kraid is a relatively normal looking three-eyed dinosaur—except for those awfully large spikes that constantly shoot out of his belly.
 * Quarians in Mass Effect are examples of Mirror Chemistry, mentioned above. They also evolved on a world where, apparently due to the strange nature of local microbes, their immune system evolved to adapt to and assimilate foreign microbes instead of rejecting them as with all other species in the galaxy. This made them extremely vulnerable to infection from more hostile microbes, though it's explained the problem is less the microbe's doing and more the efforts of the quarian immune system to assimilate it. Three centuries in sterile spaceship environments has only made their immune systems even weaker, forcing them to live permanently inside sterile suits.

Web Comics

 * The insectoid Cirbozoids of Starslip Crisis take this to an intentionally comical extreme. For starters, they reproduce asexually (the exact process is never shown); have alkaline blood they can spray through their vestigial eyes—they see with their antenna; they have dorsal gill slits that become clogged with excess blood and need to be purged periodically to keep their hearts from stopping; their carapaces secrete Ritalin; their vital organs are held in their abdomen, making almost their entire body expendable; and their natural mode of walking is skipping. Once, Memnon praised the natural artistry in some crystalline structures in Jinx's cabin; they were the result of the Cirbozoid equivalent of a head cold. And they can only breathe out.
 * On multiple occasions, the ship has been saved by any of a variety of gases or fluids that the Cirbozoid crewmember produces. Once, early on, he asks that they get some security personnel so that they can get along without the constant need for his secretions.
 * As today's comic (Tuesday, September 9, 2008) demonstrates, Cirbozoids are quite literally a Do Anything Species-if you have a need to be met, a Cirbozoid can probably use some highly specialized reproductive processes and give you a temporary to cover for you until the permanent replacement arrives.
 * It's not only their bodies that are different, but their brains; they are incapable of understanding art. This becomes a major plot point.
 * Daria is a dragon who on a whim decides to live with humans. While she's very interested in tools and technology, she is completely repulsed by the fact that humans eat, of all things, PLANTS! Her later revelation that fairies eat bugs spurs her to try to fix this problem, but she forgets about it almost instantly.
 * In Goblins, Kin the yuan-ti (basically a human with a snake tail instead of legs) mentions that she has two stomachs.
 * In Exiern Dragons leave their young in the still smouldering embers of burnt out buildings, the baby dragons resemble normal human infants and grow up looking like (and thinking they are) humans until they reach their late teens when some sort of homing instinct draws them towards other dragons. They spend some time in a half-human/half-dragon state while they gradually lose their human identities, before growing into their final dragon form.
 * Also squirrels "reproduce by magical cloning and there is but one all-squirrel connected through a collective psychic consciousness".
 * The tentaculas of Love and Tentacles. Not only do they have three different types of tentacles with very distinct purposes, they also have a two-pronged tongue.
 * Gunnerkrigg Court has at least two Merostomatozons, one of least bizarre features being that they "have 47 eyes and 15 not-eyes". Also, descendants of a.
 * Drive has Skitter, who can detect gravitational waves with his mohawk.
 * Homestuck's trolls. They have a caste system divided between 11 normal blood colors (the "hemospectrum") which goes from short-lived, psychic rust-bloods all the way up to violent & dangerous bluebloods and sea-dweller violet bloods. They have an insect-like life cycle and are born from a separate mother grub species which takes in genetic material carried by drones in pails. Genes from couples that feel the strongest love or hate for each other tend to win out of the incestuous slurry, and troll gender is irrelevant to reproduction. And that doesn't even go into all the bizarre anatomical details hinted at by "auricular sponge clots," "bone bulge," "chitinous windhole," etc.
 * Trolls sure are weird!
 * Hitmen for Destiny has this down to an art form. These usually come in the form of Professor Lostclock Dripkettle's incredibly descriptive narratives about the various odds and ends of the monsters that inhabit the many worlds of the comic from the stomach monsters who find their prey through living portals that lead to a giant stomach; to the fibra, who may very well be the least efficient creature to ever live.
 * In Irregular Webcomic, Iki Piki has a "splanch" (at least he does before his organs are harvested). It's purpose is unexplained, except that without it he'll die. The Darths and Droids version of Zam Wesell has one as well.
 * Uryuoms from El Goonish Shive have this in spades.
 * Their antennae provide low-grade telepathy used instead of pheromones and to copy languages by rubbing them on someone's head.
 * They are mildly polymorphic. Also, can "remember" forms acquired artificially (of course they developed devices for that).
 * They are technically sexless, though may imitate conventions of species who aren't. It normally takes two individuals to make an "egg", but only due to the amount of secreted substance needed. Once the egg (which looks like a meteor) is formed, DNA samples of anything can be put inside via openings, and it will naturally create a new viable chimeric being capable of shapeshifting between hybrid and parents' forms, and usually not sterile, though often asexual. Any number of sources can be used ("the current known record... is twelve"). And need not even have an Uryuom as one of the genetic parents - though it gives some perks, thus an egg itself doesn't pass Uryuom DNA and only acts as a "cross-compilier". Basically, they reproduce via a genetic engineer's wet dream.
 * The fun part is that aside of the mechanisms, these functions together make surprising amount of sense biologically. Eggs could be symbiotic organs (much like mitochondria) whose primitive ancestor was stealing pre-evolved ferment sequences. Uryuoms may walk into any biome, domesticate or fend off "interesting" local critters, stick a few drops of blood into eggs, and raise as their own a generation of Greater Chimera already adapted to this environment - not enough of them fertile to be a competition, but enough to reliably keep a symbiotic society. Then they easily maintain communication within and between populations - no matter what vocal apparatus the original species had, a chimera can shapeshift half of the way, Uryuom shifts halfway and syncs the languages in seconds. If you thought Hive Caste System is too efficient, this cheating beats it twice before breakfast.
 * Schlock Mercenary has sophonts ranging from mostly-humanoids (who also show occasional surprising twist, like having symbiotic moss for "hair") to really weird.
 * Uklakk have two bodies connected by radio link (which with some effort can be [//www.schlockmercenary.com/2002-05-16 wrapped in FTL communications]).
 * Three known sophont species (so far) are known to be capable of surviving in hard vacuum at least for a while: F'Sherl-Ganni (apparently by virtue of genetic engineering), Carbosilicate Amorphs (whose metabolism is so exotic on account of evolving from data storage systems of all things)... And then there are the [//www.schlockmercenary.com/2015-09-06 Esspererin]: they have three legs, two hands, two pairs of wing plus wing cases; are capable of atmospheric flight and talking air-breathers' language, but (along with their whole bizarre [//www.schlockmercenary.com/2016-05-01 ecosystem]) [//www.schlockmercenary.com/2016-05-26 remain functional in vacuum] and microgravity indefinitely due to — come on, you should have suspected that by now.
 * Oafa are living hydrogen blimps.
 * A lot of fauna in an ancient Oafan habitat adapted to symbiosis with either really weird microbes or runaway Oafan nanobots, that deposit metal on their skeletons/exoskeletons. This includes vaguely dragon-like Giant Flyers and bugs who evolved.

Web Original
"M'Lai: Every time they are inseminated, they get a fresh injection of the hormone. They are literally fucking themselves stupid."
 * The K'kriki'i, an alien race from the Global Guardians PBEM Universe, look like poodle-sized crickets, which isn't all that bizarre... but each individual K'kriki'i is made up of six to eight crickets apiece. Human scientists still haven't figured this one out.
 * The Aa are a technological race that resemble nothing on Earth more than a freshly baked lasagna. They have... things... in their semi-liquid makeup that function as organs... but what they are specifically, and how they function? Nobody knows.
 * Chakona Space gives us the Faleshkarti, whose semen contains a hormone that makes their partners stupid. Permanently.


 * note that the Faleshkarti are hermaprodites, and also that they have very very high sex drive, particularly at the onset of sexuual maturity. As a result, the children do a lot of the important work, including scientific research.

Western Animation
"Rattrap: What's with you two? Is my gearbox hanging out or something?"
 * Futurama has fun with this trope all the time with crustacean life-form Dr. Zoidberg. Losing organs is merely a minor nuisance for him. In the "Roswell that Ends Well" episode, he manages to keep up a running commentary during his own dissection-- "Removing the heart." "Take, I've got four of them!". In the Fountain of Youth episode "Teenage Mutant Leela's Hurdles", he regresses through an improbable number of larval stages (one example: coral to trilobyte). In the same show, Kif Kroker (the second-most-often-recurring alien) has a camouflage reflex, a fluid-filled bladder system instead of a skeleton, and a bizarre reproductive system that causes him to become pregnant from holding someone's hand. His species also begins life as a tadpole, develops into an adult, and spends the final stage of their life as a swarm of flying hookworms.
 * Subverted in "Bender's Game": Zoidberg is a monster in the dungeon. Leela rips out his heart and bites it. Zoidberg replies "Oh, as if cutting out only ONE of my two hearts would - oops!" And of course, Leela then removes his other heart, killing him - though this is further subverted by him coming back as a severed head.
 * It's possible that Dr Zoidberg's incompetence as a doctor is because, to him, humans have a bizarre biology that his species have trouble understanding. He's also not the sharpest claw on the lobster though.
 * Confirmed in the episode "The Tip of the Zoidberg". He is actually mentioned and seen as a very competent doctor when it comes to alien biology.
 * Kif has a relatively human form, except he's got three nipples and an inexplicapable belly-button. How would someone who was born from an egg have one? He also has no bones. He's got balloon-like air bladders to do the job.
 * Maybe it's a sporacle or a jellybutton.
 * You don't have to be born from a womb to have a belly button, birds and reptiles have umbilicuses too. The embyro in the egg is connected by external blood vessels to both to the yolk and a layer lining the inside of the shell through which the embryo "breathes". It's just not obvious on the adults due to scales and feathers getting in the way.
 * Kif's people aren't born from eggs. The pregnant male gives live birth to a bunch of tadpoles, which then go into a swamp.
 * Perhaps that's where his tadpole-stage gills used to be, before he reabsorbed or shed them?
 * Transformers are a race of sapient machines, hence it might not even be proper to refer to what's inside them as "biology" at all. Their inner workings still often get referred to, however, as well as other things that have a biological equivalent.


 * Not to mention that they are "born" from blanks made, probably, of Nanomachines (though that's a later addition), and their Sparks can be transferred into new bodies.
 * This has led to a lot of fans assuming that "gender", as far as the term applies to sentient robots, is more affectation than anything, and that all that's required for reproduction is a constructed body (at most; some postulate that a "pregnant" Cybertronian can also grow a new body as well as generate a new Spark) and two Cybertronians. Any two Cybertronians.
 * Actual canon meanwhile, has gone even farther in the "gender is purely decorative" area, demonstrating that all you need to create a new Cybertronian is a blank body and the local MacGuffin (Vector Sigma node, Creation Matrix, or Allspark, depending on the universe). Pregnancy doesn't even factor in, and their reaction to finding out how bizarre our biology is, is about what you'd expect the reaction of someone who reproduces by MacGuffin to be if they heard how fleshlings reproduced.
 * The G1-series' Quintessons had five faces arranged radially, and seem to have been cybernetically-modified organic life forms rather than pure robots.
 * Many aliens on Ben 10:
 * Just for starters, there's the one that's made entirely of living crystal, which it can fire as a weapon and shape into weapons and tools. Or the one that's on fire... and catching a cold turns it to ice. And then there's Ghostfreak, which is weird even by alien standards.
 * What's even weirder is that many of said aliens can interbreed with humans. This includes the species who are on fire and whose home world is a sun.
 * Roger of American Dad. He regularly excretes some sort of yellow, slippery substance from his sides. If he doesn't get his bitchiness out, it turns to bile and poisons him. He can also gain all the memories from someone by anally fingering them. He can run at Super Speed, is fireproof, and can implode a grown man's head with an elbow dive; the latter two abilities he was unaware of. And he has an extremely long lifespan, as of the show he is over 1600 years old and still apparently quite young.
 * Cathy Smith and her grampa in Monster Buster Club look externally human; she is a peppy blonde ten-year-old and he a hunchbacked old man with a big bushy mustache. When not posing as humans, however, they appear to be some kind of mutant hybrid between a flies and fish. Also their bones are made of rubber. They're good guys, though.
 * Bip in Here Comes the Grump. He can detach his nose, and he turns around by pulling his head and tail into his body and popping them out again on opposite sides.