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Bizarre Alien Reproduction

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The Xenomorph life cycle.note 

Wuffles: You are misinterpreting what you saw, Pieter!
Pieter: I saw the tentacles! I know what that means!
Wuffles: My reproductive organs are in my mouth! It doesn't work that way!

Okay, you've got your Humanoid Aliens. But no matter what you do, they don't seem alien-y enough. So you add some Bizarre Alien Biology. What's the easiest way to do this? Sex! Guaranteed to appeal to somebody, and if done right, it can look like something other than just being a pervert or possibly Fanservice. It should be added that no matter how deviant it seems to us, good sex is sometimes interspecies.

Sometimes related to G-Rated Sex. May fall into Artistic License – Biology, if the reproductive method fails to generate enough offspring to maintain a population. Note for examples to not include anything related to cultural practices; we're limited to the biology of reproduction here. Put examples belonging to subtropes on their own pages, please.


Compare Bizarre Sexual Dimorphism. If this trope is averted even when it shouldn't be, we're dealing with a Male-to-Female Universal Adaptor.


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    Anime & Manga 
  • The Twelve Kingdoms has a truly weird reproductive system involving marriage but apparently no sex: when you get married, a fruit called Ranka grows on a tree, and out of it pops your baby. What makes it far weirder is that sometimes the Ranka fruit gets blown across the sea and is implanted in a Japanese woman — this is how the central character of the anime, Youko Nakajima, would have been born, though she thought she was a normal Japanese girl until she was taken by force from her high school. In addition, royalty and other immortals can't marry — and since Nakajima becomes a queen, that includes her — and so they can't have children unless they were married before they become immortal. While it's established that they DO have sex it's apparently only done for fun, with no connection to the reproductive process at all.
  • In Dragon Ball Z the Nameks have only one gender (Males). They reproduce by puking eggs containing their offspring out of their mouths. This greatly confuses Bulma. She gives Dende a lesson that's very reminiscent of The Talk, only for him to ask what a woman is.
    • Whis alludes to this during Dragon Ball Super when he comments that he thought pregnancy was only carried by the female in humans (which it is), but he could easily be misremembering. This implies that other methods, like Namekians, are not uncommon.
  • JoJo's Bizarre Adventure: JoJolion introduces the Rock Humans, a species of Silicon-Based Life that closely resembles humans and who give birth to live young, but that's where the similarities end. Not only do their offspring only gestate for six months, but they're born 2.8 centimeters long and are abandoned by their mothers in the wilderness shortly afterward. To survive, baby Rock Humans parasitize giant wasps and hornets, surviving by burrowing into the body of their queen and feeding off her nutrients. They do this for 17 years and then molt, growing to full size and bursting out of the hive. Because of this method, Rock Humans have no concept of social bonds or family.

    Comic Books 
  • The X-Men have fought The Brood, a race of intelligent Captain Ersatzes of the creature from Alien. A human implanted with a Brood egg will eventually be physically (and mentally) transformed into a Brood member, and will retain any genetic-based abilities (e.g. mutant powers) the victim had.
  • In Phil Foglio's Buck Godot: Zap Gun for Hire's "The Gallimaufry" storyline, a male alien Pog member named Qvakk states that he loved Oort, another male of his species/race, and was "gonna take him home, make lots of eggs".
  • Transformers in IDW's Transformers comic have a truly bizarre reproductive cycle that doesn't even involve sex of any kind. There are "hot spots" on Cybertron and its moons where sparks form and are then "ignited" by an energy pulse from Vector Sigma, the life-giving core of Cybertron. This is known as 'forging'. Once the sparks are lit they are carefully removed from the ground and placed within a special kind of incubator known as the 'protoform', which it merges with. It then begins to take a form usually based on the person whom it has the most contact with as a protoform, and rapidly begins to develop the parts it needs for its future alt-mode. This all takes less than an hour, and the development from 'sparkling' into a full-size adult takes about two weeks.
    • They can also artificially reproduce through "cold construction," which supposedly involves surgically removing a portion of the spark from another cybertronian and using it to grow a new one. There was much bigotry towards cold constructed bots in Cybertron's old days (to the point of there being a Cybertronian apartheid) as they were seen as blasphemy towards Primus but it's more or less died out after the Great War.
    • Forging is also shown to have some strange limitations on it. For example, following the departure of most of the Thirteen Primes, sparks from Cybertron and its moons just...stopped forging more than one assigned sex, leading to a Cybertron so dominated by male-presenting robots that post-war some of them have trouble remembering that there are feminine pronouns. The thing where artists would put in the occasional Fembot in flashbacks and pre-War stories was eventually resolved by having them all be transgender (and frantically patching the parts of Arcee's background that had Unfortunate Implications to lock her in as a proud trans woman whose murderous rampage was related to Jhiaxus's terrible aftercare). Some of the colonies have their own quirks: Camiens have blue energon instead of pink due to different spark frequencies, Devisiens are born as twins who form a combined altmode, Eukariens all have beast forms and so on.
    • This trope is also deconstructed; this form of reproduction is so bizarre and impractical that when the life-creating pulsewaves from Vector Sigma started dwindling to a stop, it put the cybertronian race in serious concern about the future of their existence. By the time of the comics all of the hot spots on Cybertron have stopped creating sparks (there are hot spots on some metrotitan-created colonies but it's not said if they're still working). This, alongside the Great War, has greatly reduced the Cybertronian population, making them an endangered species in galactic terms. Until the end of The Transformers: More than Meets the Eye. Between the shell-shocked alternate-universe transplants from Functionist Cybertron and the newborn wave of sparks spawned on Luna-1 by Rung's Heroic Sacrifice, eventhe loss of Cybertron and most of its colonies to Unicron's hunger hasn't pushed them that much closer to extinction.
    • We later learn in More Than Meets The Eye that cold construction actually involves taking essence from the Matrix (an ancient artifact) and using it to grow sparks in a lab, making transformer biology even weirder.
    • Mad Scientist Mesothulas/Tarantulas in Sins of the Wreckers and Requiem for the Wreckers turns out to have invented an entirely separate form that actually does use the system cold construction was falsely represented as using — igniting a spark using someone else's. It's used successfully exactly once; the result is the Wreckers' leader, Springer.
    • The G2 comics feature an Big Bad who wants to return Transformers to their original reproduction method of budding off of each other. The problem is that this dilutes the divine essence invested in them by Primus, the creator god, causing successive generations of budded Transformers to grow increasingly cold and amoral. The waste products generated by the process also ended up becoming a Transformer-eating Horde of Alien Locusts.
    • Transformers (2019) mostly does away with cold construction, with Cybertronians emerging from a specific location with bodies half-made, but no altmodes until they choose them after a mentoring period. Occasionally something wonky happens, like Cliffjumper emerging later as an unexpected "twin" to Bumblebee. Titan sparks are also born from this location, but Perceptor has been keeping them in a vault because the only way to have enough resources to build a Titan would be the exact kind of expansionistic war that the Nominus Edict is supposed to prevent.
  • In an issue of Blue Beetle, Jaime Reyes, having been teleported to Reach space, hitches a ride back to Earth with a space smuggler called Moonrunner. He suggests that they shake hands and agree not to betray each other, but Moonrunner refuses because he doesn't "like [Jaime] that way", at which point the scarab informs Jaime that Moonrunner's species reproduces by shaking hands.
  • Venom's species, the Symbiotes, reproduce asexually by having each individual spawning a child once in its life. Venom gave birth to Carnage that way, while Carnage himself gave birth to Toxin later. However, Venom had several additional "seeds" capable of producing more Symbiotes which were artificially extracted and grown from it by the Life Foundation to make Riot, Phage, Lasher, Agony, and Scream. It's currently unknown if reproducing with these seeds naturally is possible.
  • Wonder Woman:
    • Wonder Woman (1942): The Rykornians are Plant Aliens that are born fully grown from husks from giant stalks resembling corn which grow from little seeds, which they also use as a food source.
    • Wonder Woman (1987): The kreel used to be gender benders as a race, capable of changing their physical sex in their later lives, but the church of the Sangtee Empire started working on making women utterly despised and socially unacceptable to the point that they are killed, enslaved or hidden away until they're able to present themselves as male and the race has relied on cloning to reproduce. Unfortunately for the raging misogynists their natural ability to change sex later in life means that cloning a man might result in a girl.
  • The Ultimates: During one of their arguments about her mutant status, Henry Pym comments on the Wasp laying "egg-constructs" once a month instead of menstruating.

    Fan Works 
  • Dragon Ball Z Abridged: Cui explicitly states that his kind "reproduce asexually". Everyone who knows that factoid is disturbed by it, and Dodoria helps Zarbon remember who Cui was (after Vegeta killed Cui) by stating the fact. Kicking a primitive Saiyan in the stomach impregnates them.
  • For Love of Magic: Veela are a One-Gender Race who can reproduce with both men and women (though the latter requires magical aid) so long as they are magical. As is eventually explained, what impregnates them isn't sexual fluids but the magic contained within them and Harry notes that the entire Veela race is closer to being clones of each other than actual relatives. Also, because they require magic to breed, Veela find Muggles no more sexually attractive than a random piece of furniture.
  • It Doesn't Work That Way: Freshly-laid dragon eggs are essentially just rocks, and are fertilized when another dragon "quickens" them by infusing them with magic by breathing fire over them. All dragons can lay eggs, but most need another dragon to fertilize them — girl dragons, which are few, are defined as being able to fertilize their own eggs. Because Spike's egg was fertilized and hatched by Twilight's magic surge, he's technically half-dragon and half-pony.
  • I Woke Up As a Dungeon, Now What?: Pixies reproduce by using their magic to cultivate "pixie groves", which in turn grow new pixies like fruit.
  • Lantern Prime: Cybertronians have two forms of reproduction. Vector Prime produces Protoforms (ala Beast Wars) which have to be initialized by one to five other Cybertronians, taking on aspects of all the parents. Alternatively, female Cybertronians (called Makers), which are very rare, can interface with a male Cybertronian, splitting off a part of each partner's Spark and gestating it until it becomes a new complete Spark, at which point it's transferred into a new body built by the Maker.
  • Monstrous Compendium Online: Most youkai races can reproduce by use of a "bloodstone," adopting a human into their clan and changing them into a new member of their species. Most of the front-line SAO players end up doing this to gain a boost in their combat prowess. They can also reproduce the traditional way, but many youkai clans have been reduced to the point where that's not an option.
  • Project Tatterdemalion, according to Vathara, is going to show that the Shinigami, Arrancar, Youkai, Akuma, and Hollows have three sexes and that all of them are necessary for reproduction. The author has stated that this requires both tentacles and psychokinesis and that the fertility rate is low and that multiples are common. Also, Ichigo is slated to have three parents: Kaien, Masaki, and Isshin, with Kaien as one of the third-sexers. The other characters who are going to go through second puberty are Kougaiji, Juushirou, Yumichika, and Retsu; those are just the ones who are known by this point.
  • Spontaneous Earth: Metamorphosis details the multiple ways a Cybertronian can be given sentience: building up a starter personality matrix that then matures through formative experience, requesting that the supercomputer Vector Sigma create one from scratch, and copying and combining several different preexisting matrices until a new one stabilizes. The fic ends by revealing that it's possible to use a brain scan of a human as a substitute personality matrix for the third method.
  • One Russian Fan Sequel to Alien³ (published in the 90s in book form along with novellizations of the three movies existing by then) reveals that the Aliens are actually a rather peaceful race which uses another species (sapient, but not very intelligent) as a host for its embryos capable of surviving the "birth". What leads to the plot of the movies is a single girl who fell pregnant out of wedlock and tried to covertly dump her kids on a race which superficially resembled the symbionts. Except they have vital organs where the latter have the womb.

    Films — Live-Action 
  • Alien: The Xenomorph life cycle goes roughly as follows:
    • Queen lays eggs.
    • Egg waits for host (human, predator, dog, whatever) to come by.
    • Egg hatches, facehugger crawls out, jumps on host's face.
    • Facehugger hangs on to host's face for day or two, host unconscious, facehugger keeps Host alive but tightens tail around neck if attempt to remove facehugger is made.
    • Facehugger lets go and promptly dies.
    • Host acts normal for another day or two (may/may not be aware of pregnancy).
    • Chestburster bursts out of chest, with some of host's DNA (eg; Chestburster from dog/ox becomes quadripedal drone instead of bipedal drone).
    • Chestburster quickly grows up into either Drone or Queen.
    • If Queen, cycle starts again.
  • Although not actually alien, the creatures from the Tremors series have a bizarre life cycle that qualifies for this trope. Eggs hatch into baby "Graboids" the size of large rodents called "Dirt Dragons", which grow into full grown bus-sized Graboids; three to six large dog-sized "Shriekers" (each capable of rapid parthenogenesis) burst from the mature Graboid at the end of it's cycle, killing it; mature Shriekers pupate, then emerge as winged "Ass Blasters", which lay eggs and are roughy the same size as Shriekers. It is shown that the entire process is asexual, with Ass Blasters developing a new Graboid egg within a matter of hours.
  • In K-PAX, K-PAXians are known to have a very painful mating experience, "like having your nuts in a vice, but all over". The process also involves nausea and a terrible smell.
  • The Lord of the Rings movies show the über-orc Uruk-Hai growing out of weird pit full of presumably magical mud stired by regular Orcs, the Uruk-Hai is born fully grown and even some times kills the stirer. This is movie-only, as reproduction of Orcs is never established in the books (and is still today subject of a lot of fan debate) but is presumably a way to represent how the Uruk-Hai were created by Saruman.

  • Shake someone's hand and introduce yourself as a space alien. Be sure not to stop shaking hands. Ask "How you doin' on Earth?" Whatever they respond, respond "This is how we doin!"

  • Animorphs
    • Yeerks are implied to have No Biological Sex, but have a form of sexual reproduction: three individuals fuse into one, which then disintegrates into hundreds of "grubs" which develop into baby Yeerks. (Occasionally one grub will turn into twins.) The Yeerk parents die in the process.
    • The Skrit Na are even stranger. The "Skrit" look sort of like giant roaches and are fairly stupid. At some point during their lives they spin a cocoon, die, but then out of their dead body a Na (basically a Grey) pops out. It's never explained where new Skrit come from, but the Na certainly have a weird way of coming into this (or some other) world.
  • The Lo'ona Aeo in Mikhail Akhmanov's Arrivals from the Dark series have four sexes. Their approximate names are male, female, half-male, and half-female. Half-females are sterile and don't participate in the reproductive process. Males and half-males join their minds with females, which starts the "mental contamination" process and impregnates the female without actual physical contact. The resulting child's personality is based on all three parents. Until their maturity, Lo'ona Aeo can artificially induce a slightly different sex on themselves using medical means (e.g. an immature half-female can make herself a female). Reproduction is directed by the heads of extended families in order to prevent unwanted genetic branches. Thus, they may force a female to become a half-female in order to cut off any possible offspring from that line.
    The novels describe a unique case of a human male (descended from a human-Faata hybrid) using his latent telepathic abilities to accidentally "mentally contaminate" a Lo'ona Aeo female. Her son ended up lacking the extreme xenophobia that all Lo'ona Aeo have and becomes an adventurer (a quality inherited from his father). Since Lo'ona Aeo live for over 1000 years, he has encountered several of his father's human descendants.
  • From Isaac Asimov's works:
    • In The Gods Themselves, the inhabitants of the parallel universe are "Soft ones", photosythetic gas creatures who have three sexes, of which one provides the seed, one the energy for the conception, and one the womb (referred to as Rational/left, Emotional/mid, and Parental/right) which reproduce by temporarily fusing at a molecular level ("melting"). After bearing three children, they "pass on". permanently fusing into adult "Hard ones", a ruler caste that act as mentors to the Soft ones and pretend they're another species.
    • In "What Is This Thing Called Love?": The alien protagonists are an asexually reproducing species. One alien researcher is trying to convince his boss that Earth animals have bisexual reproduction, although neither one really understand the difference between mating and courtship, and the subjects they kidnap are too embarrassed to explain anything.
    • "Does a Bee Care?" describes an alien whose life-cycle is going to a planet, infiltrating it and influencing the growth of science and technology, and hitching a ride from one of their starships to fertilize other planets. The kicker is that all this is done unconsciously on instinct.
The ovum spilt him forth at length and he took the shape of a man and lived among men and protected himself against men. And his one purpose was to arrange to have men travel along a path that would end with a ship and within the ship a hole and within the hole, himself.
  • The alien city dwellers from Blind Lake have two stages in life. The sentient adult form is neuter and has a special feeding apparatus which the parasitic larval form require in order to survive. It's the larvae that actually do the breeding. On occasion, a larva is infected by the virus present in the adults and will transform into an adult itself.
  • The mantis-like Ki! from Chess With a Dragon are hermaphroditic parasitoids, who implant eggs in "host-grubs" of various non-sentient species including feral human children they only think are dumb animals.
  • There is a lot of this is Piers Anthony's Cluster series; every species has a different, exotic way of breeding, and of course the hero, as he Body Surfs between the species, experiences them all.
  • The Color of Distance's Tendu hatch in great numbers as tadpoles or narey. Eventually they metamorphize into froglike tinka, and live in the forests for a time until going into a village and acting as servants. Some tinka are chosen and treated to transform into bami, able to speak and reason and somewhere between children and apprentices. Bami, when those they were chosen by die or are exiled, are transformed again into sexually mature elders. Rarely elders will choose to become enkar, but this last stage is more a cultural than physical change. All levels eat some of the plentiful fertilized eggs and narey, and few tinka are chosen so that most die of animal attacks or old age, in order to help keep populations down.
  • The Nac Mac Feegle in Discworld has one female to a tribe, who is the Kelda and is married to the most powerful warrior. It's her job to do the thinking for the entire tribe and, although she's their ruler, she's also, in a way, a prisoner. Female births are very rare and girls are expected, upon reaching adulthood, to either find a tribe whose Kelda has recently died or collect a few men from nearby tribes to form a new tribe. In either case, she takes some of her brothers with her to keep her company until she gets to know her new people. Incidentally, Terry Pratchett was quite interested in bees and their swarming behaviours.
  • Between their advanced knowledge of the universe, their shape-shifting nature and the wide range of powers they are able to borrow from each other, the Gods and Demons of Divine Blood are capable of this even if it's not their normal choice. They are canonically capable of:
  • The Doctor Who New Adventures novels suggest that Time Lords are all sterile and are "born" from a "Loom", a machine in their giant sentient semi-organic family Houses. Each Loom weaves Family members according to a common template, ensuring that they're related; every Family member is a genetically a cousin to each other.
  • The Fire-lizards of the Dragonriders of Pern series (and consequently the dragons that were engineered from them) have two kinds of female and three kinds of male, though only one male and female of any of the types is required to produce offspring of all types. Further, these are typically of one specific set of types (gold and bronze) as they are respectively the most intelligent and best endurance flyers of the different types. How exactly this system came about is never explained, nor does it appear to be shared by any other native species on Pern.
  • In the world of The Egg Man, pregnancy results in the birth of a myriad of "fetus flies", tiny humans with wings, who fly off and live like wild animals across the urban landscape, with most of them dying before they're old enough to walk. The ones who do grow to the point where they resemble regular children are caught by one corporation or another and raised to become corporate citizens.
  • The Hosts in Embassytown have a cycle that's skimmed over, but there is an initial aquatic phase of life, where the young Hosts are referred to a "elvers", a terrestrial phase where young play and fight, middle age and sapience, and their final phase, lumbering and nonsentient. They evolved to reach that phase and wander mindlessly after younger Hosts who at the time would eat them, but modern civilized Hosts, with no need of that, abhor the idea and treat elders kindly until they drop.
  • From Everworld: Male Hetwan, though usually little more than perfectly obedient drones for their deity Ka Anor, will immediately go nuts and mate with any female they see, which looks like a living collection of guts. A collection of eight to ten offspring are born immediately — which is good, because the males rip the females to pieces while having sex.
  • The Rozes, troll/giant hybrids from the Garrett, P.I. series, claim to be "triplets with different mothers". Garrett has never been inclined to ask for details, so we don't know if it's this trope or a cultural thing.
  • The Phagors from the Helliconia trilogy have a cyclical libido, such that males are compelled to mate once every few days. They barely ever think about sex otherwise, yet the fact that such matings are conducted without any pretense of privacy, just as a human might sneeze in public, leads most humans to consider them lustful perverts.
  • How a Realist Hero Rebuilt the Kingdom: Dragons' human forms are born Otherworldly and Sexually Ambiguous, but shift to take on masculine or feminine forms based on the sex of their humanoid riders, who are also their mates. This has the side effect that only dragons who partner with males can birth new dragons, since female humanoids cannot lay eggs. Dragon reproduction runs on Either/Or Offspring, with the other possibilities being the race of the non-dragon parent, or a Half-Human Hybrid race (dragonewts from Western-style winged dragons, sea serpents from Eastern-style ryuu like Souma's partner Naden Delal).
  • In Robert J. Sawyer's Illegal Alien, the Tosoks' females have four wombs, so that group sex is the norm for them, with four males impregnating each. Half-siblings are also far more common as a result. Occasionally though just one male inseminates all four of a female's wombs. Their term for God possibly even reflects that — one human, learning about all this, reflects how they thought the Tosoks were saying "Foremother" but it may have really been "Fourmother".
  • Though they can breed perfectly fine with humans, Martians in the John Carter of Mars series lay eggs for some inexplicable reason.note  Yes, even the Half Human Hybrids.
  • Larry Niven's Known Space: Most species in Known Space other than humans (and other hominids) and dolphins have a pretty thin time of it when it comes to sex. It's kind of Niven's trademark. It's likely that the Moties, who die if they don't get pregnant, were Niven's idea rather than Pournelle's.
    • When asked, the Puppeteers say they have three sexes, but it's not quite accurate. What they have is a "sperm depositor" male, an "egg depositor" male (really a female), and a non-sapient "female" (actually a different species that reproduces among themselves in a different way) called a "Bride". The Puppeteer ovum is deposited in the flesh of the Bride, the egg is then fertilized, and when the egg hatches, the infant puppeteer eats its way out of the body of the "female". In the Fleet of Worlds novels, it's revealed that this is invariably fatal to the Bride. This is based on real-life parasitoids, although these instead have the male fertilise the female who then lays fertilised eggs in a host. The Puppeteers are a bit squeamish about this, and consequently pretend that their host organisms are a willing third sex.
    • Jotoki hatch as wormlike, nonsapient tadpoles. As they mature, a group of these combinies into a five-limbed, five-brained alien that achieves higher intelligence through its components collective brainpower but has a habit of arguing with itself.
    • Trinocs do not have distinct sexes and do not typically reproduce purposefully. Instead, every so often, a group of two or more Trinocs will exchange quantities of the structured plasm that makes up their bodies. Usually, this only refreshes them. Occasionally, however, one, some or all Trinocs involved in this process will grow polyps on their bodies, which are then detached and nurtured in a nutrient-rich bath. Not all polyps survive, but those that do become infant Trinocs.
    • The hominids of Ringworld kind of make up for it by having robust interspecies sex a regular part of trade and politics.
  • The mental patient "prot" from the novel series K-PAX describes the K-PAXians' mating process as being extremely unpleasant, involving profound pain, nausea and a potent terrible smell. The books tie this in with a kind of Immortal Procreation Clause — since the K-PAXian lifespan is over a thousand years, combined with the unappealing mating process, there's no problem with either under OR overpopulation.
  • Gethenians in The Left Hand of Darkness are an engineered Human Subspecies who are usually asexual and genderless, but go through a stage each year called kemmer, lasting about 25 days. While in kemmer a Gethenian will become either male or female with no control over which sex they take, unless they use certain chemicals. During kemmer their body is essentially in a state of Mate or Die, so incest during this time is generally not frowned upon, certainly during pubescence, unless it becomes a romantic attachment. They might "keep kemmer" (have a long-term partner) or "vow kemmer" (the equivalent of marriage), but the vast majority of Gethenians are polygamous during kemmer, and most openly visit kemmer-houses to mate with whoever else happens to be there.
  • Lilith's Brood: The Cthulhumanoid Oankali have an "ooloi" third sex who collect DNA from male and female parents, genetically engineer a blastocyst in a specialized organ, and implant it into the female through their skin. On their own, Oankali children are born to those three parents, but their Half-Human Hybrid children add a human father and mother to the mix.
  • The life cycle of the Tyr in The Madness Season proves important to the plot of the book. Their homeworld has a century-long highly elliptical orbit. At the closest approach, the Raayat-Tyr, which serve as drones, return to the homeworld and fight each other through the hive in an attempt to reach the queen. A Raayat who mates with the queen will be killed. But, if the Raayat kills her, he will transform into the new queen.
  • Medea: Harlan's World was a collaboration between a number of major SF writers to create a single setting, and a series of short stories set on the titular moon. In Flare Time by Larry Niven, the reproductive cycle of the native sentients known as fuxes is described. They start off as six-legged females. At around seven they have their first litter, during which their rear body segment tears off, leaving them as four-legged females. The hindquarters contain the eggs, and function as a nest which the newborns eat their way out of. Around seventeen they have a second litter, leaving them as two-legged males, with the male organs exposed through the loss of the second body segment. The male guards the nest until the young are born, then goes into heat for about three years, and eventually ends up a 'post-male'.
  • The Moties in The Mote in God's Eye have an interesting cyclical reproductive cycle. All Moties (of any subspecies) are born as males. After a time, they shift to female, after which they have maybe a couple of years to get pregnant and give birth. If they fail to do so, they die of hormonal imbalance, while if they do, they shift back to male and the cycle restarts. The resulting series of population explosions and wars over territory has resulted in their undergoing species-wide societal collapse more times than they can count.
  • The My Teacher Is an Alien series makes mention of a species that requires "five genders to produce an egg, and another three to hatch it". It's a kids series, so we aren't given any details on how this works.
  • The main alien race in Greg Egan's Orthogonal trilogy is a gold mine for this trope.
    • Sex immediately induces reproduction; there is no gestation period.
    • Sex consists of two of the Shapeshifting aliens melding the flesh of their chests, through which the male transmits a light-based signal into the female's body to induce the reproductive process. No actual matter or bodily substance is exchanged; genetic diversity is ensured through the infrared transmission of "influences" by every individual to everyone around them — which, incidentally, is also how diseases spread.
    • Females reproduce by splitting into four children; two sets of male-female twins respectively referred to as cos, who are genetically ideal mates for each other. The children who are not cos to each other are referred to as brothers and sisters, but the same terms are generally not used to refer to cos, probably to avoid implying that the relationship between cos is Brother–Sister Incest.
    • In the rare event that a woman is born without a co note  or is otherwise unable or unwilling to mate with her co, she can instead reproduce with another willing male, known as a co-stead. These relationships are treated more as a husband/wife relationship than the relationship between cos. It's considered a kind of reproductive Undesirable Prize, generally resorted to only when one co is dead or nonexistant, but there are occasional exceptions.
    • Under the right circumstances, primarily old age or spending too much time away from their co or co-stead, spontaneous reproduction is common enough to necessitate women taking a drug to prevent it.
    • In The Eternal Flame, things get even Weirder Than Usual: A woman fasting to the point of near-starvation helps to both stave off spontaneous reproduction as well as to ensure that, when it happens, it will result in only one pair of cos instead of two, for Population Control.
    • And even weirder note : Near the end of The Eternal Flame, the biologist half of the Ensemble Cast develops a way to induce childbirth that produces only one child, does not kill the mother, renders her sterile for the purposes of traditional (fission) childbirth, and is shown to be repeatable in the final book, and can produce male children. In other words, they can more or less reproduce just like us.
  • Reborn as a Space Mercenary: I Woke Up Piloting the Strongest Starship!: In volume 2 we find out that Space Elves like Elma are only fertile with people they love. This can apparently cross species boundaries, since we learn it in the context that she's informed by a doctor that male lead Hiro can get her pregnant. Being the resident tsundere, she is less than pleased by this.
  • The Pequeninos of Speaker for the Dead, the sequel to Ender's Game. To reproduce, the male has to be ritually vivisected to turn into a tree. Infant females are brought to the Fathertree and crawl around on its bark, absorbing sperm through its dust. Also: any female that survives to adulthood is completely sterile; the young eat their way out of the infant mother's body. Both male and female young are nursed in the Mothertree, which is what happens when a sterile adult female turns into a tree, which exudes a highly nutritious sap the young feed on until they're large enough to walk around on the ground.

    In fact, all native life on the planet is like this (for example, there are no male herd animals—the grass they graze on fertilizes the females). They were changed by a virus, brought to their planet by other alien species. All species who didn't develop bizarre reproductive cycles died.
  • Since Starfish Aliens in Star Carrier are the rule not the exception, it stands to reason that this trope is played straight most of the time. The described examples include the Agletsch and the Grdoch:
    • The Agletsch appear to be Insectoid Aliens but are not. The spider-like individuals are all female. Their males are small non-sentient grubs that the females keep attached to them at all times. When the time comes, the males fertilize the females.
    • The Grdoch look like large balls with senses and mouths all around. Each Grdoch acts as both parents, fertilizing itself. The young are born inside and stay there until they sense distress in their parent, at which point they pop out and try to get away. The Grdoch lack any paternal feelings towards their young and frequently used them to distract larger predators or even as a light snack. In space, small, chaotically bouncing shapes can prove to be a hazard on any ship, but the Grdoch haven't found any way of preventing that, especially during battles, where the stress causes such "births".
  • Vonda N. McIntyre's Starfarer series has the squidmoths. The juveniles exchange gamete packets with each other and keep the packets they receive (the packets can stay fresh for a long time). At some point the juvenile consciously chooses to undergo a metamorphosis, consumes the collected gamete packets, lays fertile eggs, and dies.
  • One of the Star Trek: The Captain's Table books presented the Anjiri and the Nykkus, two species of Reptilians whose gender (female, male, neuter) was determined by the temperature at which their eggs were incubated. Originally, they were presented in a fairly straightforward Planet of Hats way — the Anjiri were matriarchal, with the females running the planet and the males being basically incompetent Space Pirates; the Nykkus were initially presented as a sort of Henchmen Race to the Anjiri. It later turned out that the Nykkus and Anjiri are actually one species with two forms; females of either "species" in fact lay eggs for both, apparently regardless of whether their mates are Nykkus or Anjiri. All the Nykkus shown in the original appearance were "Coldborn" (neuter and not very bright); the male and female Nykkus shown later have little interest in working for the Anjiri, although the females are a lot better disposed towards them. Oh, and incubation temperature also determines, or at least strongly influences, both intelligence and physical strength (with females being the strongest/smartest for each race).
  • Star Wars Legends:
    • Khomites can only reproduce by cloning. They also only eat dietary supplements.
    • Selonians have one fertile female and a handful of males per 1,000 births. They're subterranean mammals; the queen and the males — presumably not from the same colony — basically do little but breed while the rest of the colony runs civilization. A little like naked mole rats. Humans and Selonians can apparently be allergic to each other. Or at least Corran and that one Selonian were.
    • Falleen pheromones work on anything in the galaxy.
    • Dathomiri women can use the Force to arouse men and then you know the rest. Teneniel does this to Luke. While he doesn't like it, he still talks to her afterward.
    • Zeltrons, Pink Skinned Space Babes that they are, have a sexual attraction to Force-sensitives. If there's one thing the Expanded Universe has driven home, it's that a lot of people have been attracted to Luke even before he married Mara — though for his part, he was politely disinterested in most of them.
    • Yevetha reproduce by the females laying eggs called "birth casks". They are external wombs, placing in special birthing chambers and fed fresh blood that gets absorbed through their shells. Any children which stayed in their eggs past birth are called "nestings". In most cases mothers are the ones to provide them blood, however it could come from any Yevetha. Other Yevetha are sacrificed to provide blood, or did so voluntarily (as this was considered a high honor when done for higher-ranking families).
    • Hutts are hermaphrodites capable of conceiving asexually (although they can sexually reproduce too).
  • Brandon Sanderson:
    • Mistborn: The Original Trilogy:
      • The koloss are an artificial species, so their method of reproduction is rather simple: Basically, the souls of four humans are ripped out and stapled to a fifth. This fifth person then mutates into a koloss. The really weird part is that koloss swords can be used to control their population. If they have fewer swords than koloss, they will fight each other over the swords until their population has shrunk enough. If there are more swords than koloss, they will create more koloss until every koloss has a sword. By Wax and Wayne, Harmony has changed the koloss so that they reproduce sexually. However, the child of two koloss is merely a "koloss-blooded," an otherwise ordinary human who is just tougher and stronger. When they come of age, they have the option to be transformed into a full koloss or leave the clan. Likewise, outsiders have the option of entering the clan and being transformed into full koloss. The clan doesn't care where someone came from once they are transformed.
      • The kandra have two stages of life: The non-sentient mistwraiths (which presumably reproduce sexually), and the sentient kandra. Kandra can only be created by giving a mistwraith special "blessings," which are hemalurgic spikes made by killing a human. The kandra have neither the ability nor the desire to make the blessings themselves, leaving them completely at the mercy of their creator.
    • The Stormlight Archive: Little is known about the reproductive process of the Rosharan chasmfiend, but one stage seems to involve the creature climbing up onto a plateau, spinning a vaguely insect-like cocoon out of what is basically cement, and waiting for one of the storms that come along every few days. Presumably, they need the Mana the storms carry to fuel the transformation to the next stage of their cycle. In the second book, Shallan points out that since the Alethi have been slaughtering pupating chasmfiends on a massive scale for the past six years, they're dealing huge damage to the ecology of the region, and it's not sustainable.
    • Though the Parshendi reproductive process itself is similar to that of humans — so much so that the Horneaters are offshoots of long-ago human/Parshendi intermarriage — how they get to the point that they mate is very unusual. The Parshendi are shapeshifters who take on different "forms" in their lives, and in almost all of their forms they have no interest in sexual intercourse. The exception is mateform, in which they are constantly obsessed with hedonistic pleasure and sex. While other Parshendi forms can theoretically have sex, they have virtually no drive to do so.
    • The diones from his Skyward series have "right" and "left" genders instead of "male" and "female". To reproduce, a right and left must merge together into a composite dione known as a "draft", which has most of the memories of its constituents but its own unique personality. After several months, a draft splits back into its component right and left, but if it so chooses it can also leave behind an infant dione which will grow up to have a similar personality to the draft that produced it. Notably, this has made it uniquely easy for diones to remove any dissent from their culture (as per Superiority values): If the draft's family doesn't approve of the personality of the draft, they simply have the draft separate without producing an offspring, then recombine and see if they get someone they like better this time.
  • Survival in Another World with My Mistress!: Harpies lay unfertilized eggs like birds, but gestate fertilized eggs internally like mammals and some fish and reptiles. Kousuke about goes cross-eyed trying to figure that one out. Also, they don't have a problem eating their own unfertilized eggs.
  • The Torin series is a low-key example; most of the visible mammalian species on Torin are marsupials, including the local sapient humanoids, who carry their infants in pouches for the first few months after birth, and are initially horrified when a visitor from Earth attempts to describe how his people carry their babies entirely enclosed within the mother with no apertures for air to get in.
  • Les Xipéhuz: The Xipéhuz, being the first example for Bizarre Alien Biology and Starfish Aliens in literature, naturally display this. Every solstice and equinox, they gather in groups of three, merge into some kind of ellipsoid and stay this way overnight. The next day, they part and leave giant smoky forms which become denser and form into cones much bigger than the adult Xipéhuz before shrinking into their adult forms.
  • Rocheworld: Flowen mate by gathering in a group of three or more (we see four), mingling their biomass, and withdrawing the colored liquid that forms their neurochemistry, then pinching off the now-clear globs of tissue, which slowly settles on a personality and color over the course of thirty seconds or so. They can also clone themselves by fission, which is exploited when their human friends recruit them to explore the rest of the Barnard's Star solar system.
  • Wayfarers, by Becky Chambers, has many alien sapient species. For most, their biology is recognisable as similar to Earth species.
    • The Aeluon have four sexes: male, female, shon (who switch between male and female) and those who are neither. Aeluon who are female, or shon during a female phase, may "Shimmer" once or twice in their lives. Their silver scales begin to glitter with a sheen of swimming colours, an outward signal that their body has produced an egg. During this period of fertility, they must have the egg fertilised by a male Aeluon, or a shon in male form. After several weeks, the mother lays a hard-shelled egg, which must be cared for in an incubation pool until it hatches. Some Artistic Licence – Biology may be involved, as this doesn't begin to approach replacement-level fertility — especially as some females and shon may never experience Shimmer.
    • Among the Quelin, a hard-shelled species of sapient with 22 pairs of legs, males incubate the eggs in "keratin pockets" which line each side of their abdomen.
    • The mammalian Laru have a pouch, where the young live for several years after birth.
  • Well World: The plant-like Czill reproduce by mitosis. The "twinning" process begins with increasingly severe dizzy spells, after which the Czill usually finds a good spot to root in and wait the process out. Over a period of ten days or so, they slowly grow a second body from their back. Eventually, the brain begins to duplicate, leading to increasingly confused and doubled thoughts until, at the end, the Czill functionally cannot think coherently anymore. Finally, the twins separate as entirely identical individuals, who then usually go on to different paths in life in order to develop fully distinct minds.

    Live-Action TV 
  • Alien Nation: Three Newcomers are required to make a baby: a male, a female, and a binnaum who catalyzes the impregnated female. Part way through the pregnancy, the female transfers the fetus to the male, where it slips inside his belly somehow and attaches an umbilicus to one of the male's nipples. It is the pregnant male who gets to have the wacky Born in an Elevator scene at the end.
  • Alien Worlds (2020): The rabbit-like grazers on Eden are under too much danger from predators to be able to take the time to court, mate and give birth. Instead, they release worm-like spawn that seek each other out, fuse into an embryo, and cover themselves in a tough cocoon. The cocoon then shoots out whip-like cords that attach themselves to trees and hoist it into the air, raising it beyond the reach of predators on the ground or in the tree branches and allowing the embryo to gestate in safety.
  • American Horror Story: Double Feature: the aliens are a Dying Race and abduct humans in order to create alien-human hybrids. However, their scientific techniques are quite otherwordly: the biological sex of the host does not matter, the pregnancy bears all the typical aspects of a human pregnancy (sensitivity in the chest, strange cravings, morning sickness) except that it is inhumanly fast, lasting for a few days/weeks ; and as for the delivery... Well, as the alien doctors say, "life finds its way"... (though it should be noted that not all human hosts die upon delivering their babies, some are able to fall pregnant several times without any threat to their life)
  • Andromeda:
    • The Magog reproduce asexually, laying their eggs in a host which then eats the host from the inside.
    • The Nightsiders are a parthenogenetic species who release their tadpole-like spawn into water and forget about them until they emerge from the water as adults. Most are eaten by each other.
  • At one point in Angel, Wesley describes how a species of demon bugs they're exterminating reproduce by regurgitating crystals that attract microbes that are mutated by said crystals into their eggs.
  • Babylon 5:
    • Centauri have six prehensile tentacles for sexual organs, which are flexible enough to (as Londo demonstrates in "The Quality of Mercy") snake under a poker table and pick up a card on the other side of the table. Centauri women have six corresponding slits on their backs. What drives this into Bizarre Alien Reproduction rather than it simply being Exotic Equipment is that the amount of pleasure from intercourse goes up for each tentacle/slit used, and use of all six is required for conception. One imagines that Centauri orgies are as decadent as their civilization as a whole (think, you could have hundreds of participants and absolutely no risk of pregnancy for any of the women)....
    • There's also the Pak'ma'ra, for whom the only reproductive information mentioned in-show is that the "hump" on their backs is actually their reproductive area. (According to Usenet postings by the creator, female Pak'ma'ra are tiny, non-sentient beings who live inside said hump.)
    • In "Acts of Sacrifice", Ivanova tricks one alien into believing that a strange dance (with nonsensical chanting) — which seem to be an abbreviated script for a one-night stand — and rubbing of hands was Bizarre Human Reproduction.note  At the end of the episode, Ivanova is left a gift by the alien: A trinket of some kind and a note saying "next time ... my way."
  • Doctor Who:
    • "Partners in Crime" introduces the Adipose, aliens made of fat that seem to solely reproduce by converting the body fat (and in extreme cases, the entire body mass) of other species into their young. They used to have entire nursery planets for this but their mysterious disappearance forces them to seek out illicit means.
    • "The Unicorn and the Wasp": The Vespiform can mate with a human thanks to phase-shifting capabilities. Thanks to phase-shifting capabilities.
    • "The Tsuranga Conundrum": Among Gifftans both sexes get pregnant, with males giving birth to males and females giving birth to females. We don't see how female pregnancies work, but males are pregnant for only a week, have a "birthing sac" that must be painlessly cut open to have the baby, and the babies are born with two umbilical cords.
  • The Future Is Wild: 100 million years in the future, the Earth has become much hotter, now with 75% of its surface covered in water. One of its inhabitants is the Ocean Phantom, a 30-foot colonial jellyfish. It reproduces by riding the giant hurricanes that ravage the future world, allowing itself to ripped to shreds by the wind and waves. Each of its pieces can then regenerate into a new Phantom.
  • Hyperdrive. Before making First Contact with an alien planet, the crew have to watch a squick-inducing Instructional Film warning them of the dangers of Boldly Coming.
    Let's learn about another Alien Sex Disease. This crew member had intercourse with a Glygonthian octopoid. Let's take a close look at his genitals. Pustules have developed. And on the pustules, warts. Soon his entire groin explodes revealing five baby octopoids, each with his face. Remember — alien sex is danger sex.
  • One episode of The Muppet Show depicts how creatures on the planet Koosbane reproduce, the "Galley-oh-Hoop-Hoop", which starts with the male doing a dance to impress the female, and then the two of them pacing off and charging headlong at each other, resulting in an explosion and a litter of babies.
  • The Orville: Moclans reproduce by laying eggs, although they are male. Or at least it seems that way to begin with...
  • The Outer Limits (1963): In "The Duplicate Man", the Megasoid reproduces asexually, and hundreds of offspring can result.
  • The Outer Limits (1995):
    • In "The Voyage Home", the alien that invades the Mars III spacecraft reproduces by releasing a spore into an organism's body which then leaves the body and replicates it. The process is fatal to the organism in question. The alien's plan was to proliferate its species by converting humanity en masse once the spacecraft returned to Earth.
    • In "Paradise", a dying alien woman who was the Last of Her Kind arrived on Earth in 1946 and met four young women. With their consent, she implanted an egg in each of their bodies so that her species would have a chance to survive. The eggs took 50 years to mature. The alien left a special light which, 50 years later, made the four women young again but only long enough to conceive. Three of them had sex with strangers in the attempt. Not only were they unable to conceive but they rapidly aged to death. Their bodies decomposed just as quickly. On the other hand, Helen is successful in conceiving a baby with Gerry, her late husband Charles' brother, as she had always been in love with him and vice versa. Within about an hour, Helen is heavily pregnant and about to give birth. The resulting child appears to be a human girl, which Helen's daughter Dr. Christina Markham and her husband Grady intend to raise as their own since they can't have children. Helen returns to her true age but her Alzheimer's has been cured as a gift from the alien.
    • In "Rule of Law", the Medusans lay eggs. During the hatching process, the hatchlings absorb energy from tritium bricks. They cannot survive the hatching process without this energy.
  • In the Red Dwarf episode "Can of Worms", the Cat becomes host for eight polymorph babies. He is warned the morphlings will seek the nearest available orifice for birth. Cut to the Cat, naked, face-down and sweating as Rimmer, Lister and Kryten act as midwives. The Cat then endures giving birth — presumably anally — to things like a Rubik's Cube with spiky corners, a very large beachball, a model cabin cruiser with sharp prow, and a pineapple.
  • Star Trek has plenty of examples, having been on TV for so long:
    • The Vulcans have "Pon farr", a mating season every seven years, where they must mate or die. Alternatively they can beat another competitor to their desired mate to death, which is just plain weird.
    • Xyrillian females can impregnate human males without the human noticing. The one time this happened in the show she hadn't been aware this was possible. They technically reproduce asexually; the "male" Xyrillians don't contribute any DNA to the process, they just carry the female's child.
    • The Q can choose to have sex by touching fingertips, but being nigh-omnipotent that's not saying a whole lot we don't already know from the "omnipotent" label.
    • The Varro mate for life, and to ensure this they intermix their body chemistry, causing symptoms of physical withdrawal if a mate leaves.
    • All we know about Klingon sex is that it's not uncommon for both partners to break bones. Ow. A broken collarbone on the wedding night is a sign of good luck. Of course, given how Klingons tend to act, that might simply be a cultural tendency towards very rough sex.
    • 90% of Taresians are born female. They claim to reproduce by implanting embryos in the wombs of females of other species, but the child will be fully Tersian. The truth is even weirder: They spread a retrovirus that turns males of other species into pseudo-Teresians, and then he's driven to return to the planet where they'll extract his DNA, fatally.
    • Female Ocampa go through "Elogium", a puberty-like stage where they can successfully conceive a child (in a growth on their back), but it only happens once. Also leads to a very large bit of Fridge Logic, every Ocampa female can only conceive once, and multiples births seem to be rare to non-existent... so if every female Ocampa can only produce one child in their entire life... how is the species not extinct already? The Fridge Logic factor of Ocampan reproduction goes far further than that: Despite only being able to reproduce once and only living for nine years, the females have constantly engorged breasts. The reason why humans have breasts and dogs don't is because we can reproduce whenever we feel like it — there is no biological reason why they should grow breasts a good four years before they can conceive. Secondly, they reproduce through a bizarre system of massaging feet and gluing their hands together for an entire week using a thick, sticky mucus — in the wild no creature could do this without being eaten by predators. This would logically mean both the males and females have nothing between their legs and are around about the same size — if this was real life and not being played by human actors and actresses the only way to determine a male from a female would be those anomalous breasts.
      • The "one mating = extinction" dilemma, at least, can be resolved if Ocampa are a sperm-sequestering species, such that one mating provides the male genetic contribution for multiple pregnancies over the female's lifetime. If said subsequent pregnancies happen in quick succession, the constantly-engorged breasts would make sense too: they don't have time to shrink between babies. However the only example we have of an Ocampan family is the alternate future from one episode where Kes had one daughter in her lifetime and the daughter also had only one child.
    • The J'naii are supposed to be genderless (although they all look very similar to female Humans). However, nothing about J'naii reproduction makes any sense, as the script muddles together three totally different kinds of genderlessness. The asexual cast to their society would make sense if they reproduced by cloning, but they do reproduce sexually, in which case being a One-Gender Race should make their interactions more sexual, not less. The persecution of those who prefer a gender would make sense for a race of hermaphrodites (where everyone is both sexes simultaneously) but Soren describes their sex act as a precisely symmetrical affair (i.e. the J'naii are all one single sex—they're isogametes.) An isogamete preferring one sex over another makes about as much sense as a Cyclops preferring one eye over another. It makes more sense after it's revealed that they weren't always this way, and slowly evolved to change. As such, having a vestige of their old sexual habits and retaining these preferences, in however small, tangential a way, does make a lot of sense.
    • Denobulans have a mating season, and their breeding drive is regulated by powerful pheromones generated by their females. Males can become violent under these pheromones' influences. Culturally, they practice group marriage, and also remain promiscuous outside such formal relationships.
    • The Kobali resurrect, and genetically alter, the corpses of other species.
    • Andorians, as revealed in the expanded universe, have four separate genders, all of which are needed for reproduction. Deconstructed in that this is revealed to be causing their genetic diversity to break down; by the time period covered in Star Trek: Deep Space Nine Relaunch, they're a Dying Race with extinction predicted within fifteen generations. And that is being optimistic. There is actually a scientific movement underway looking to retro-engineer them back into being a two-gender race, which is meeting severe opposition from many Andorians, as the four-gender quartet is an integral part of their culture and religion.
    • And then there's Star Trek: Deep Space Nine's often mentioned but never seen Lieutenant Vilix'pran, who on several occasions was said to be "budding" — a process which, according to various bits of related dialogue, can produce from two to twelve hatchlings and requires a pond.
    • During seasons 4 and 5 of DS9, Major Kira was a surrogate mother to the O'Briens' child after Keiko O'Brien suffered a serious injury. During that time, we learn that Bajoran pregnancies last 5 months instead of 9 months like humans, and instead of suffering morning sickness, pregnant Bajoran women have intense sneezing fits.
  • Torchwood: Season 2 gives us the Nostrovite, in which the male carries fertilized eggs in their mouth, passes them on to a suitable humanoid host (and that makes the host look nine months pregnant overnight), and then the female comes to claim the ripping it out of the host.
  • In the original V (1983) miniseries, Willie recognizes Robin is pregnant because she's developing a ring of discoloration around her neck, which suggests that such rings are normal for Visitor mothers-to-be. His comments imply the ring becomes more complete as the pregnancy progresses.
    • In a sense, this is Bizarre in how normal the reproduction was. The Visitors are reptiles from another world posing as humanoids (presumably mammalian). Somehow Robin was impregnated through what appeared to be intercourse, just like it would be between humans.
  • The V (2009) remake is a little strange. The normal V reproduction involves a queen (like Anna) mating with a male, after which she eats him for nutrients. She then lays hundreds, if not thousands, of fertilized eggs with one or two being "queen" eggs. While initially thought impossible, it's discovered that Half-Human Hybrids are indeed a possibility but may be more V than human. Only one was shown onscreen, the product of a V father and human mother. However, the final episode shows a queen V mating with a human and taking a bite out of him, implying she has been impregnated.
  • The Greys in The X-Files are capable of incubating inside a human host who has been infected with Black Oil. When the hosts gets hot enough, the alien hatches into a long-clawed, violent creature that desires more heat. Eventually, it sheds its skin to become a "normal" grey alien.

    Oral Tradition 
  • The Greys are apparently extremely interested in human sexuality for some reason, so we are ourselves a case of Bizarre Alien Reproduction, inverting this trope among UFO nuts.

  • Mission to Zyxx: Dar's species has reconfigurable genitalia that make sex with literally anything possible. Though there is no transfer of genetic material, the act can result in parthenogenic pregnancy resulting in a clone of the parent.

  • The Hitch Hikers Guide To The Galaxy 1978:
    • We're never told the details, but the Betelgeusians Ford Prefect and Zaphod Beeblebrox in share three mothers (with the implication that Zaphod at least has more mothers who they don't share), which makes them "semi-cousins".
    • Ford's father "both fathered and uncled" him, which could mean Ford is the product of incestuous relations, or just more of this trope.

    Tabletop Games 
  • Chaosium: The All the Worlds' Monsters supplement describes Scarlet Stalkers, which capture human beings and insert eggs into their bodies. The eggs keep the humans paralyzed until the eggs hatch and the young eat their way out of the body.
  • Dungeons & Dragons includes multiple examples, mostly among the Aberration creature type.
    • Illithids reproduce asexually and deposit eggs in the pools of their colony's elder brain (which is itself formed from the discarded brains of dead illithids). These eggs hatch into four-tailed tadpoles that cannibalize each other for several years while also avoiding the predations of the Elder Brain, which feeds on their psionic energy. Tadpoles that survive to maturity are then inserted into the nostrils or ears of captive humanoids to devour and replace the nervous system, transforming their host into an adult illithid in a process known as ceremorphosis. Occasionally, one of these tadpoles matures into a larger, stronger illithid called an ulitharid. This individual eventually leaves the colony alongside an entourage of lesser illithids to found a new one; once the new colony is established, the ulitharid removes its brain, which is planted into its body and grows into a new elder brain to repeat the cycle. If an illithid tadpole doesn't find a host, usually if its colony is wiped out and the elder brain slain, it will venture onto land and start hunting to survive. Should it feed on a sentient creature, consuming the brain triggers the same growth spurt as ceremorphosis, but without a body to inhabit, the tadpole grows into a monster called a neothelid, a fully-sentient, dragon-sized, slime-caked worm with a mass of tentacles for a face, psychic powers, and the ability to spray acid. Illithids prefer not to talk about them, since neothelids are just as willing to prey on them as anything else.
    • Beholders also reproduce asexually. After spontaneously self-impregnating, they gorge themselves until their womb becomes too large and pinches their esophagus shut. When the children come to term, the parent vomits up its entire uterus (which does not regenerate), examines the swarm of tiny beholders for those that most resemble their parent, and chase those off while consuming the rest for looking wrong. 5th Edition's Volo's Guide to Monsters replaces this with a more bizarre method: sometimes, a beholder may create another beholder by dreaming — a beholder that dreams of existing in multiple places or of looking into a mirror will wake up to discover that a duplicate of itself has come into being. Other dreams instead give rise to the various species of beholderkin — for instance, beholders who dream of blood or wounds may create the vampiric death kisses, while one obsessing over a draconic rival may dream an eye drake into being.
    • In Fifth Edition, Hags propagate by snatching and devouring human infants. After stealing a baby from its cradle or its mother's womb, the hag consumes the child. A week later, the hag gives birth to a daughter who looks human until her thirteenth birthday, whereupon the child transforms into the spitting image of her hag mother.
    • In most editions dragons are assumed to reproduce in the usual manner vertebrates do. Fifth Edition's Fizban's Treasury of Dragons admits that this may likely be the case on at least some worlds, but posits some additional means by which dragons make little dragons:
      • Parthenogenesis — the least unusual of the lot, a dragon simply laying a clutch of eggs without needing to mate. This may happen spontaneously or after the dragon consumes a prodigious quantity of treasure.
      • Five adult or older dragons of different breeds come together and sacrifice a bit of their life energy to create a clutch of five eggs. The breeds of the resulting eggs will match the makeup of the conclave that formed them.
      • When dragons reach advanced age, they can enter a deep trance, die, and reform as an egg.
      • Dragons physically craft their eggs through painstaking labor, and magically breathe life into them when done.
      • Enlightened humanoids become dragon eggs after death or by performing a specific magic ritual.
      • Dragon eggs form from the bodies of dead dragons, which can take the form of them growing from their parent's rotting carcass like fungus, being left behind after the dragon's body is consumed by fire, or being mined out of a dragon that turned into solid stone or metal after death.
      • Dragon eggs grow like fruit from a tree somewhere in a distant corner of the world. Dragons in a family mood must track this tree down and talk its warden into giving them an egg.
      • Dragon eggs arise naturally, with metallic dragon eggs forming within veins of metal, gem dragon eggs forming within deposits of precious minerals, and chromatic dragon eggs forming in extreme environments such as the hearts of volcanoes, arctic wastes, primeval forests and the like. They may hatch on their own, or when dug up by someone else.
      • Dragons cannot reproduce. All dragons are the fruit of direct intervention by the gods Bahamut or Tiamat, who are the only beings who can create new dragon eggs.
    • Magerippers reproduce by budding off young from their backs when especially well-fed on magic.
    • Mystara: The wallara chameleon-men are a One-Gender Race species of Lizard Folk who, being only male, rely on a magic-based form of reproduction where they shed their skin once per year and then place it inside a "tookoo", a sacred shrine of their race. These carefully bundled skins have a chance of being transformed into new baby wallaras, which are then raised by the rest of the clan.
  • Exalted: Demons tend to reproduce in very bizarre ways, when they're able to do so on their own at all. In fact, actual sex is one of the few things that cannot create a new demon, and they tend to find sexual reproduction to be just as bizarre as humans find the demons' own methods of procreation.
    • Gilmyne reproduce through a particular dance where four such demons circle closer and closer until they merge. A moment later, five demons part and go their separate ways.
    • A chrysogona's bite causes its target to turn into wood like that which makes up the demon itself. Mortals eventually die from this, after which a new chrysogona bursts from their shell.
    • Erymanthoi reproduce through pain. When an erymanthus is seared with vitriol and its skin is pierced with iron spikes at very specific points, it emits a howl of agony that transforms into a new blood-ape.
  • Infernum: Both demons and the spawn (Hell's equivalent of animals) have this.
    • Spawn reproduce by dying; when you kill a spawn, multiple smaller, weaker spawn of the same kind will emerge from the corpse within a minute or two. Kill those, and even more spawn that are even smaller will emerge, ad infinitum, until the resultant spawn is too weak to "divide" in this fashion anymore and simply dies upon death.
    • Demons, meanwhile, reproduce through Spawning Pits... which manage to be even less fun than they sound like. Spawning Pits are filled with alchemical acids that dissolve living demons, but catalyse their organs, causing anywhere from one to thirty-six "larvae" to chew their way out of the decaying husk. After about six months, these maggot-like creatures pupate inside cocoons and then emerge as demons of the same kind as their "parent".
    • Making things even more bizarre: demons and spawn are related to each other. The first demons were born when fallen angels had sex with spawn.
    • Oh, and demons are fully capable of producing human/demon crossbreeds through sex, if they take the Noble Mutation that lets them develop a fully functional gender (or are malcubi, who are the only demon subrace to innately have functional genitalia as humans understand them). Such demons are also capable of producing rare "mixed-breed" demons if they mate with each other, although this is very uncommon due to a mixture of paranoia and how difficult it is for demons to carry offspring to term, as it notably increases their daily requirements of nourishment.
  • RuneQuest:
    • Green, brown and yellow elves mate like humans (or, at least, human scholars are reasonably sure they do). After this, however, the female elf gives birth to a coconut-sized seed, which is then planted and grows into a plant that bears a single fleshy fruit. After two years of maturation, the fruit is split open to reveal an elf child equivalent to a 4- to 6-year-old human infant.
    • The Slorifings — also called red elves and goblins — are all male, and reproduce by worshipping a type of love spirits. After a successful worship session, the supplicant buries himself and goes into eternal sleep. Afterwards, a spore-bearing plant such as a fern sprouts over his grave and produces a crop of miniature Slorifings, which are called imps and treated as adults from birth.
    • Dwarves aren't born as such; in fact, they find sexual reproduction repulsive. Instead, they're essentially manufactured. The process requires a male-female pair to spend a few weeks using their respective "mortar" and "pestle" to create the blank template of a dwarf (the dwarves find this process horrific, and usually suppress their memories of the event). This is then placed in a caste-specific container to brew for a number of years, before being decanted as a young dwarf ready for labor.
  • The Strange: Hydras assimilate the heads of their victims into their collective self if these possess useful knowledge or skills. If a hydra gains more than it can easily manage, it will shed some of its excess heads and these will braid together to form a new hydra.
  • Traveller: Hivers are a Starfish Alien race that reproduce in an equally unusual manner. Any time that two Hivers meet, they interlace their rearmost arms and exchange genetic material (humans have dubbed this "shaking hands"). Both Hivers then produce a larva, which they shed from their bodies some time later and chase out into the wilderness (Hiver cities are always surrounded by predator-filled wilderness for exactly this purpose). Only a tiny fraction of the Hiver larvae survive, which is the point — Hivers are born nonsapient, but can develop sapience if they are repeatedly forced to confront danger and solve problems as larvae. Those that survive long enough to develop sapience make their way back to the nearest Hiver city, where they are taken in and raised collectively by the Hivers therein.
  • Warhammer 40,000:
    • Orks are partly fungus-based; they shed spores throughout their lives that can grow into any kind of Orkoid lifeform, and release a large number of spores upon death. They qualify as Alien Kudzu in that every single Orkoid has the potential to grow into a full "Orkiformed" ecosystem. The only way to prevent this is by burning the bodies.
    • Tyranid Genestealers implant genetic material in victims that causes them to form a cult-like devotion to the Genestealer and a drive to mate. Each generation spawned by the cult members will look less and less like a Genestealer until the fifth or sixth generation, which exactly resembles the host species. The next generation will then be "purestrain" Genestealers, and the cycle will start over.
    • The fluff book Xenology hints that, while Eldar appear to procreate in the same manner as humans, males may have to make multiple deliveries of genetic material to fully conceive, as opposed to humans. The actual canonicity of this has never been established, though.

    Video Games 
  • The Galka in Final Fantasy XI are an all-male race who reproduce via a form of reincarnation. When a Galka is nearing the end of their current life through natural causes, they sense it and go on a spiritual pilgrimage to a high mountain and await their current life's end. According to Galkan beliefs, a magnificent light will appear and grant that Galka a new younger body, and seemingly fragments of the memories of their past life. No one else has witnessed this miracle, and no Galka recalls their personal experience of the matter, so there's some who believe it is simply folk lore. But there appears to be truth to it, because after a Galka leaves for their final journey, a new Galkan child arrives to the same Galka village within less than a year latter. No one however, is sure how Galkan's then replenish their numbers, due to death from violence or illness.
  • Flip Dimensions: Despite appearing to be humans with demonic powers and having angelic origins, real Nephilims seem to be born as larva that are fully capable of combat.
  • The Legend of Zelda: Tears of the Kingdom reveals in a side quest that the rocky Gorons are born from the land (at least the land around Death Mountain) rather than reproducing the way other Hyrulean races do.
  • Minecraft: For most breedable mobs to breed, the player needs to feed two of the same species (there are no sexes) a specific food item related to their species, or if two villagers are "willing" in the case of villagers. Then, the two mobs will head towards each other and start "kissing" (moving into each other), and after a few seconds a baby mob spawns nearby, which grows up after a period of time passes. The only exceptions to these are turtles and frogs, where one of the pair will head to a location to lay eggs that hatch into young after time passes, which makes turtle and frog reproduction bizarre compared to how all other mobs breed. Chickens also have a second method of breeding, which is via thrown eggs having a chance to hatch. There's also Allays, intangible fairy-like entities who clone themselves when given an Amethyst Shard while dancing to music from a music box.
  • Mass Effect
    • Asari reproduction is based on "melding". During said process, the asari scrambles and changes up a DNA sample of her own, using the DNA of her partner, whatever sex and (sentient) species it may be, as a map/inspiration. The randomized version of the asari's genes is then combined with an unchanged sample of them for purposes of producing offspring. Sexual contact is not required, but not uncommon. Even more weirdly, mating within their own species is discouraged in order to avoid certain extremely nasty genetic defects that can occur from such a union. The offspring are also not considered asari/whatever hybrids, but are always just asari. The species of the father seems to have some effect on the child (an offspring of asari/krogan is gleefully coarse and violent, asari/vorcha offspring are allergic to dairy, and Mordin at one point guesses an asari had an elcor father based on her body), but the "nature vs. nurture" influence is unclear.
    • Salarian females lay eggs throughout their lives, several a year. Fertilized eggs hatch as females, unfertilized ones as males. In order to keep from overwhelming their worlds, salarians only fertilize 10% of their eggs, using extremely complicated reproductive contracts to arrange who does what.
    • Because of the incredibly lethal Death World they're native to, krogan females are capable of producing thousands of offspring (it's never mentioned whether they lay eggs or give live birth, but given their generally reptilian appearance it's probably the former).
    • One of the more disturbing examples in the series is the Reapers, which melt down an entire sentient species into some sort of goo, which they mold into a new Reaper.
    • The kett in Andromeda actually cannot reproduce; all sex organs on them are vestigial. So how are new kett made? They transform members of other species into new kett via a highly painful process referred to as "exaltation". The Archon implies that they have assimilated over a thousand species into more kett.
  • In Patapon, you create new individuals by burying certain materials under a special tree.
  • In an old Maxis game, Unnatural Selection, genetically engineered creatures reproduce via "melting into a skin colored blob, combinating and laying a baby version of themselves" you can watch this here.
  • Pikmin. The tiny Pikmin apparently reproduce by bringing plant matter and insect corpses back to their "onions", which serve as their hives, which then spit out seeds that plant themselves into the ground, mature for a while, and then get uprooted as new baby Pikmin. It's also possible that they require another creature (such as the player) to uproot them in order to enter their mobile phase and complete the cycle.
  • Guilty Gear. While it's All There in the Manual, Gears apparently lay eggs or the children come out in a protective cocoon they later hatch out of.
  • Myst: One of Atrus's journals describes an other-Agely creature called a "ting", which seals itself in a rock crevice, from which a bunch of lizard-like "solastings" emerge a couple of months later. It's unstated how the solastings give rise to the next generation of tings.
  • Seaman has the titular human-headed fish creatures, whose life cycles and reproductive habits are, to say the least, bizarre...
    • Seamen start out as Mushroomers, a larval form that more closely resembles floating eyeballs with tiny tails for locomotion. The only way for Mushroomers to survive after hatching is to be ingested by a host creature — in this game's case, a nautilus — which they feed on from the inside out before bursting out of the host's body, fully formed in their next form...
    • The Gillman more closely resembles the creatures' iconic form, albeit small and childlike in behavior and speech at first. Gillmen are initially incapable of intelligent speech, but as the player talks to it, its vocabulary will expand until it is able to carry conversations. Gillmen will cannibalize one another by draining blood from their broodmates via their cranial tendril until only two remain, with one becoming the "male" upon being named, developing a golden coloration to their scales.
    • In time, the two remaining Gillmen grow into Podfish, evolving primative legs while retaining their Gillman appearances. Eventually, the Podfish mate via the "male" mounting the other Podfish and connecting cranial tendrils, after which the "male" Podfish dies. After converting the aquarium into a terrarium, the remaining Podfish will use its legs to crawl onto solid ground, lay its eggs, and die.
    • These eggs hatch into Tadmen, which resemble juvenile Gillmen, albeit appearing more like mature tadpoles. Like Gillmen, Tadmen will cannibalize one another until only two remain.
    • The remaining Tadmen eventually grow into Frogmen, resembling frogs with human faces. As a lifeform capable of living both in water and on land, Frogmen become fully independent and capable of surviving on their own.
    • In the Japan-exclusive PS2 remake, there is a subsequent form of Seaman called the Lizardman, which is born from two Frogmen mating and laying a single egg that hatches into a Lizardman.
    • There is an additional form after Lizardman in the Japan-exclusive sequel called the Birdman, which resembles a seagull with a human face, but how a Seaman reaches this form is unknown.
  • In Spore, Alien Animals dance together, then one of them lays an Easter egg (and then you can see if you have enough DNA stored up to tweak your critter for the next generation.)
  • Sonic Adventure: Chao reproduce when one Chao sits in a bed of flowersnote  and is joined by another Chao, the two proceeding to nuzzle and dance until an egg containing attributes from the two appears between them. Most Chao enter the flower phase naturally with time, though it's possible to induce it by feeding the Chao some heart-shaped fruit.
  • Dwarf Fortress:
    • It has been suggested that many of the species reproduce via spores rather than in the conventional fashion, given the way that you can chain up members of different sexes at opposite ends of the fortress and still get offspring.
    • A more deliberate design choice can be seen in the form of night trolls, single gender monsters who kidnap members of the opposite sex, transforms them into "spouses", and proceed to reproduce in the normal way. The children are always the same sex as the night troll parent, and the spouse is often slain or simply abandoned (which inevitably means death at the hands of their former species). Notably, night trolls are happy to prey on elves, dwarves or humans, but goblins just don't do it for them.
  • In the X-Universe the Teladi lay eggs that always hatch females if left unfertilized. For this reason space Teladi are effectively a One-Gender Race.
  • Much like Xenomorphs, Chryssalids in X Com Enemy Unknown plant their seed into living hosts by viciously murdering them and vomiting eggs into the corpse, which turns humans into shambling zombies. If a zombie is left alive for too long, it will burst into a newborn Chrysalid, identical in size to a "mature" one, but with lighter skin color.
    • in XCOM 2, the Evolved Chryssalids don't need to directly kill the host or even inject eggs in order to reproduce anymore, they merely need to poison the host. If the host dies while the poison is still in effect, they rapidly transform into an overgrown cocoon, which releases multiple newborn Chryssalids one at a time, three per corpse.
  • While it's never shown how sex among Pokémon works, some aspects of their reproduction are defintely weird:
    • Every species is part of one or two egg-groups and could mate with any other pokémon of the same egg group as long as it's of the opposite gender, even if there is vast size differences between the two. The offspring will always be of the female's species, but with some of the male's moves.
    • Ditto is a genderless Pokémon that can mate with any other fertile Pokémon regardless of gender. The offspring is never Ditto, but always the other Pokémon's species.
      • The only exception is Manaphy, which will always produce an Egg containing a Phione (which cannot evolve into Manaphy).
    • Some species are male-only or female-only. The male-only species can only reproduce other members of his species with the help of Ditto. How these Pokémon propagate without Ditto's help is unexplained.
      • The only exceptions being the Nidoran-line and Volbeat/Illumise, where male and female are regarded as different species, but the female can produce offspring of the male species, even if her male is of a different species.
    • Some species are genderless and only able to mate with Ditto. Much like Male-only species, how they do it without Ditto isn't explained.
    • Some species cannot reproduce in-game, but some of them are seen to have eggs or babies in other media. An event in Pokémon Sun and Moon allows you to get a Cosmog by bringing a Solgaleo or Lunala to a different "version" of Alola and allowing them to meet with the Lunala/Solgaleo of that world. The Cosmog instantly appears after the "meeting" but the player doesn't get to see the exact details of what happens.
    • And the daycare-owner still doesn't know where the eggs come from. Some dialogue with NPCs even suggest that Pokémon eggs aren't even eggs in the biological sense and are more like "cradles"... No explanation is given as to what this is supposed to mean.
    • Nihilego, an Ultra Beast, does not breed like regular Pokemon, but Concept art shows that it breeds by spawning polyps that grow into larvae and then adults. Basically, it reproduces like a real jellyfish. Other Ultra Beasts may have other methods of propagating that are different from the standard "male-and-female produce an egg in a daycare", such as Celesteela sprouting from the ground in its home world.
  • Trials in Tainted Space is an erotic Space Opera which has the player boldly going to new planets to earn their fortune while Boldly Coming into every alien they meet. While almost every alien has average human genitals the Nyrea have something far different. The males lack penises, instead, they have sperm sacs inside a cavity in their hips. The larger female uses her spiked ovipositor, an organ that looks like a horse penis with spines at the tip, to rend the sperm sacs and suck up the sperm to fertilize her eggs. If the female is an alpha of her group, she will make a lesser female gestate her eggs. Yeah.
  • Starbound:
    • The Glitch is a race of robots made to simulate evolution. Part of their programming is an inability to realize that they aren't ortganic beings (though now and then a Glitch manages to break past the blocks), so they have a lot of internal blinds, including when reproduction is concerned. When a Glitch couple decide it's time to start a family, they retreat to their bedroom. They then enter a trance-like state and proceed to a secret workshop none of them are consciously aware of, where they assemble their new offspring. Upon completion, they leave the workshop and return home, after which they snap out of the trance. They will have no memory of the event, but are convinced that it was "very pleasant".
    • The Floran are a race of plants and are technically genderless beyond cosmetic details. While nothing canonical is clarified about their reproduction, their respawning animation shows a seed sprouting into a pod that opens to release a reborn Floran. Early beta versions also had "Floran pods" planted in fields. Presumably, the Floran reproduce by pollination leading to seeds that are planted and produce offspring without internal gestation.
  • Xenoblade Chronicles X:
    • The Orphe are a vaguely insect-looking species that reproduce asexually. The method is by sprinkling some "senirapa" water upon themselves (even a single drop will suffice), which causes their body to spontaneously generate two new Orphe. The children possess all the memories of their parent. It is common for dying Orphe to do this as their final act, to ensure that their memories and experiences will not be lost, but the game suggests that they can do it at any time they please, as long as they have some of the water on hand. And this is before one Orphe randomly undergoes a mutation that leads to the sudden birth of the first female of their species.
    • The Zaruboggan seem to be a One-Gender Race, and also reproduce asexually. The precise method isn't gone into, but the word they use for producing a child is "regurgitation".
  • Despite being technically undead, the Draug of The Secret World have a very detailed and extremely unusual reproductive cycle: upon finding a large quantity of corpses — or producing them — the Draug mages will resurrect the dead as zombies; from there, the broodwitches will inseminate these zombies with their tentacles, remaking them into Incubators. As the Draug egg inside them grows and swells, the Incubators will roam the area in search of a safe place to nest, before finally planting themselves in the ground, having completely transformed into a large egg-sac. Eventually, after careful treatment with enzymes from the Broodsources, red weed and organic fertilizer, the egg-sac will split open and disgorge a new Draug warrior. For good measure, old Draug who haven't been lucky enough to become Stronger with Age will eventually melt down into the fertilizer used to grow the next generation of Draug.
  • Saya no Uta has this come into play during one of the game's three Downer Endings: Saya came to Earth to convert the planet's dominant species, humans, into her own race. To that end, she has sex with a human — specifically, Fuminori, the only human not repulsed by her Eldritch Abomination nature due to a brain injury making him see everything else as abject horrors. After absorbing his genetic information via copulation, she releases spores into the atmosphere that rewrites the human genome so that everyone will transform into her race.
  • The Elder Scrolls:
    • The Lizard Folk Argonians are easily the most "alien" out of the playable races, being cold-blooded reptiles who are the only playable race which didn't descend from the Ehlnofey.note  The Argonians are an oviparous (egg-laying) sapient species, with the females also possessing Non-Mammal Mammaries. According to some (potentially dubious) sources, the Argonians are also sequential hermaphrodites, meaning they can switch genders. The time spent as either male or female is called a "life-phase".
    • The Sload "slug men" are another very alien race native to the Thras archipelago to the southwest of Tamriel. Born into broods of aquatic, amorphous grubs whose parents "care little" for them (and even actively kill them in order to produce the alchemical ingredient "Sload Soap"), those who survive grow into "squishy" adolescents likened to octopi. Further, adult Sload are believed to be hermaphrodites who absorb their sexual organs by the time they are capable of surviving on land.
  • The Xel'naga of Starcraft reproduce via two separate species, one with purity of form (psionic power) and one with purity of essence (Cannibalism Superpower), merging together and being granted the essence of the previous generation of Xel'naga. Then they find a new universe, seed it with life, and hibernate in the void between universes until the next two races find them.
  • Goblins in West of Loathing are a kind of sentient, ambulatory fungus. They can bud off short-lived spawn for battle, or they can "pop" into a cloud of spores, to be dispersed by the wind and eventually grow into adult goblins. The goblin pardner Gary wants to find a suitable location for popping.
  • The Last Sovereign: The succubi and the orcs.
    • Sex or more specifically semen is required for impregnation as with humans, but succubi can willfully control when they want to get pregnant, obviously useful for a race of nymphomaniacs. Additionally, semen can be absorbed anywhere on the succubus body. Males from any species can conceive with succubi as can orcs (who are otherwise sterile) or succubi utilizing “futa” spells and regardless of the father, the children are always succubi. Succubi using “futa” spells on women of any other species doesn’t work, however. So, a bit like a sexier version of how the asari do it.
    • Orcs naturally feel a primal urge to fuck women of all races, but despite this all orcs are sterile and can only father children with succubi, which can reproduce with any sapient species. Instead, as orcs grow older, gain experience, and have sex, they grow larger turning into ogres. Once an ogre has reached the upper limit of growth it splits into smaller fully formed orcs and the process repeats. If Succubi are similar to Asari, then orcs are more closely a mix of generic hentai orcs and Warhammer 40,000 Orks, combining the former's uncontrollable sexual appetites with the latter's continuous growth and asexual reproduction.

    Visual Novels 
  • Contract Demon: Demons are incapable of reproducing sexually. The only way to make a new demon is to have a mortal sell their soul to a contract demon. When the mortal dies, they suffer a Death of Personality as their soul is transformed into a newborn demon.

  • El Goonish Shive: Uryuoms have one sex (but identify as male or female if in a society that recognizes gender, like the USA). It normally takes two individuals to make an egg, made by secreting a certain substance — it takes two only due to the amount needed. Once the egg (which looks like a meteor) is formed, it lacks any DNA of its own. DNA of anything can be put in (through the openings that make it look like a meteor), and it will naturally create a new viable chimeric being inside it. Any number of sources can be used (the current record is twelve). There need not even be an Uryuom as one of the genetic parents. Basically, they reproduce via a genetic engineer's wet dream. And yes, some genetic engineers have noticed.
    Nanase: What... ethnicity is Grace, anyway?
    Tedd: Mixed. Very, very mixed.note 
  • Homestuck:
    • Troll reproduction is extremely strange, although the comic is often light on the particulars. As said in the comic, "Trolls sure are weird!"
      • They reproduce by "mixing genetic material"note  with their lover and their archenemy in separate pails, and then give the material to a drone. Gender is irrelevant to reproduction. All of the combined material is then basically mixed together, and a mother grub takes the best material and lays eggs for the whole species.
      • Alternian society expects all capable trolls to donate material in this way; if a troll doesn't have a mate for both of these, the drones kill them for not being able to fill both buckets. The horror of this comes from the fact that trolls arrive at sexual maturity around the same time as humans do and are at the same level of emotional and mental security. These are kids put to work sexing it up the second they are capable of "producing genetic material", and they have no idea what the hell is going on. Trolls also have a different idea of romance than humans do, with four types to humans' one type — one is normal romance, one is based on hate, and the other two types of romance are non-sexual and instead based on mutual emotional support.
      • Infant trolls are birthed as caterpillar-like "wrigglers", which cocoon themselves in the birthing caverns and mature into humanoid children. The baby trolls are then raised by one of dozens or hundreds of different types of "lusi" (singular "lusus"), which are different animal species that presumably reproduce normally. They have a symbiotic relationship with trolls, where they adopt and raise troll children, as trolls never know their parents.
      • This has the side-effect of making pails (and pictures thereof) Not Safe for Work among trolls, as seen here note .
    • Universes themselves have a bizarre means of reproduction, which involves Stable Time Loops, a video game which manipulates reality and draws the players into the game, a war between anthropomorphic chess pieces which one side is always destined to lose, and sped-up frog breeding. The end result of this process is the creation of a cosmic frog that contains an entire universe in its body, hosting civilizations that will one day play the game again and produce another universe frog.
    • Cherubs are even weirder than trolls. They can only mate with rivals, by a ritual where they typically go onto a black hole and turn into enormous, near-indestructable snakes that can only be harmed by one another. Whoever loses the battle is impregnated with the young, and the Character Alignment of each child depends on which parent carries the young.
    • Leprechauns are possibly weirder than cherubs, although we've been spared the details. Their bizarre alien romance involves combinations of nine emotions, one of which equates to human love or troll matespritship, and most of which involve pranks and riddles. Unlike the four "quadrants" of troll romance, any of these relationships can lead to reproduction, following a "mating jig". Oh, and they're a One-Gender Race.
  • Freefall: Only a small number of Sqid are fertile, and those breed early. Upon breeding, both the male and female die. A litter of young is born and, Sqids being scavengers, the Sqidlings have a ready-made food source. Other adults come along and pick Sqidlings to raise (a process described as being like picking a puppy). These "Mentors" raise the young Sqid in their race's ideals of chicanery and stealing everything not nailed down or on fire.
  • Schlock Mercenary:
    • The title character is a carbosilicate amorph, essentially a race of organic data-storage systems turned sentient. They typically reproduce by splitting off a part of themselves that contains their personality, and merging it with that of another. On top of that, due to the "sentient data-storage" bit, it's also possible to reproduce with non-amorphs through a period of observation — a process Commander Kevyn compared to marriage. On top of that, two amorphs battling it out usually results in, rather than one or both parties dying, a single amorph with merged personality traits of both combatants.
    • The Qlavo conceive normally with males and females, but hand off responsibilities of development to a third gender, muftales.
    • This goes on, as a whole rather more than we see. Even humans are not exempt; most pregnancies are handled in cheap artificial wombs, and births are performed on the kitchen counter.
  • Twisted Tropes: Captain Kirk saves Zeta-2 and asks the Green-Skinned Space Babe for a "suitable reward". She rewards him with Naughty Tentacles and pregnancy. The strip description comments that him hooking up with Dejah Thoris is just as likely as humanoid Sarlacc.
  • Heartcore: The demons of Asgard reproduce by dying — if a demon decides they're tired of life, they're replaced by an egg holding their reincarnation, which will also have attributes from another demon they've been in contact with. After two years, the new demon will require the originator's Heartcore.
  • Outsider:
    • The Umiak didn't fit this at first, but nowadays they've biologically and cybernetically modified themselves so much that they might not even have any sort of natural reproduction cycle. Almost every Umiak seen is a clone of some sort.
    • The Barsam are hermaphrodites who reproduce by regurgitating egg-like gamete sacks, which another individual then swallows to impregnate themself.
    • The Pipolsid, a species of radially symmetrical and vaguely jellyfish-like creatures, reproduce by budding, and can transmit some of their chemically-stored memories to offspring produced this way.
  • L's Empire: Kayoss reproduce by holding hands. Each Kayoss can only mate with one person, even if that person isn't a Kayoss, or in Void's case, alive.
  • In Bardsworth, fairies are a female One-Gender Race. When a community wants more members, they do a ritual with some part of nature (usually a young tree) and something like thirty baby fairies result. A species called the Arbori the same way, as do the all-male demons, though their version is implied to be nastier.
    Mike: So...your dad is a tree?
  • Blood is Mine: The protagonist was hatched from an egg, even though she is half human. The details of this are not given.
  • According to A Petty Nuzlocke Challenge, the Geodude family of Pokemon explode as a form of asexual reproduction. Part 2's Broseph the Geodude is a fragment/spawn of Part 1's Broseph the Graveler who detonated himself in combat.
  • Dragon Sanctuary: There is always a set number of Draconians in the world. When one dies and their corpse is burned, a new one is created and grows to maturity within one to five years. At no point do they ever mate, and their families are based more on bonds rather than any blood relations.

    Web Original 
  • Aegeroth: A Checkered History: The checkered knights reproduce by laying their eggs in the neck stubs of their decapitated victims.
  • In "Body Shifters Universe", the aliens are human-sized bacteria that shapeshift into whatever form a person finds most attractive, absorbs the DNA and divides into two more shifters who continue to mate with the nonshifter parent.
  • Looming Gaia:
    • Cecaelia are in many ways "alien" compared to other naturally-born peoples of Gaia, including their reproduction: Males fertilize the eggs that the females laid with no sex involved.
    • On the monster side, Spriggans turn into trees in old age, which grow pods where baby spriggans hatch from.
  • Nightmare Beings: One user's dream was a bird that laid clutches of orange eggs that each had a pair of insect legs, and walked around forming long trains together.
  • Red vs. Blue: It's not what the exact process of reproduction is for aliens, but in the end, somebody's going to get infected with an alien parasite and give birth. Even if they're male. And the alien in question is male too. It's like a miracle to see nature at work!
  • SCP Foundation
    • SCP-149 ("The Blood Flies") are mosquitos that reproduce by injecting a retrovirus into the human body that changes cells into fertilized mosquito eggs. When the eggs hatch the mosquitos leave the body through the mouth, nostrils and eye sockets. This invariably kills the victim.
    • SCP-150 ("The Prosthetic Parasite") burrows into a human body and changes the nearest limb (arm or leg) into SCP-150 tissue covered with a chitinous exoskeleton. The victim is mind-controlled into removing the limb, which then hatches out more SCP-150 larvae.
    • SCP-538 ("Shadow Spiders") reproduce by biting a victim. After about an hour the victim suffers a horrible death and their shadow breaks up into pieces. Each shadow piece becomes a new shadow spider.
    • SCP-631 ("Nyctophobic Nocturnal Predator") eats the internal organs of a sleeping human victim and lays its eggs in the body. When the eggs hatch an hour later the babies eat the body.
    • SCP-632 ("Intrusive Arachnid Thoughts") are small spiders that reproduce by exposing humans to sensory triggers, including seeing the patterns on their abdomen, feeling them crawl on the skin, or via chemicals emitted from adults. This causes baby spiders to grow inside of the victim's brain and cause a worsening headache. The victim's attempts to stop the headache via eventual trauma splits the head open to release the adult SCP-632.
    • SCP-695 ("Eels"): Juvenile SCP-695 perform an Orifice Invasion on a male human, grow to adult size and lay eggs. They then force the host to rape a female human and infect her with the eggs. The eggs will grow into juveniles, which will leave the female's body through either an Orifice Evacuation or performing a Chest Burster out of her abdomen.
    • SCP-1092 ("A Species of Fish") reproduces by having one of its eggs enter the body of a large mammal through a cut and grow to adult size (up to 2.1 centimeters) inside the mammal's blood vessels.
    • SCP-1294 ("The Laughing Fox") is a fungus that reproduces by mating with a female fox. Its offspring grows inside the fox and eventually escapes as a Chest Burster.
    • SCP-2401 ("Mary Had a Little Lamb") are unusual honeybees that can infest and control a human body, but males all die quickly and most of the females commit suicide. When the host body is female it can have sex with a human male and become impregnated. The babies will be adapted to be better hosts.
  • Serina: All life on Serina is descended from Earth organisms, but that doesn't stop one clade of birds from evolving this.
    • One early clade, the vivas, give birth to live young by retaining their eggs inside the mother's body until hatching.
    • The changelings, or metamorphs, reproduce more like a fly than a bird: the mother lays tiny delicate eggs in a carcass or larder of meat and abandons them. These hatch into near-embryonic young with only a head and forelimbs developed at all, like newborn marsupials. The "larvae" eat and grow continuously until they secrete a mucous cocoon, from which a wholly normal-looking tropical bird emerges. Later forms have more specialized larvae, some which are skin-breathing and aquatic, while others are Sand Worm-like predators.
      • The changelings' descendants, the ornimorphs. Instead of forming a cocoon, a baby ornimorph gradually grows from a tadpole-like aquatic larva through amphibian- and reptile-like juvenile stages, before becoming arboreal, growing feathers, becoming first a glider and then a true flyer and eventually coming to resemble a mostly-typical bird.
      • The placental birds are another group of changelings that pass their early larval stages inside the mother, attaching to the wall of the uterus and continuing much of their development within, until the young born live in a much more developed and independent state, often precocial at birth.
    • Bloons and birdwhales are fully marine birds descended from pelican-like seabirds that have adapted to carry their eggs in their throat pouch. After millions of years of evolution this pouch has fully separated from the digestive system and become highly vascularised in order to provide heat and oxygen for the egg, effectivly becoming a pseudo uterus.
    • The bumblets evolve the ability to give live birth by retaining their egg internally and oxygenating it by... flatulence.
  • Snaiad: The two-headed vertebrate-analogues have their first heads contain their genitalia. Mating is accomplished by "kissing", and young are "vomited" out by the parent at birth.
  • Triaformica: The speculative alien species has three sexes, but only needs two, each of a different sex, to reproduce. Sexual organ-wise, they're all hermaphrodites and the organs are in their chests, accessable via a normally airtight hole into which they stick their own tongue during mating to get their own set of sex cells. Then they stick their tongue into the hole of their partner while said partner is in heat to drop the cells into. The whole process takes about a minute and, while it feels 'nice' to them, it certainly isn't as pleasurable in the same way as humans.
  • Worm: The Entities undergo a sort of mitosis, the adult producing multiple offspring once it has finished experimenting with shards and consuming all available nutrition. The offspring then depart by detonating the planet they are currently on. Different lineages have varying forms of reproduction due to divergent evolution.

    Western Animation 
  • Adventure Time: "Bonnie and Neddy" shows how Princess Bubblegum/Bonnibel and her brother Neddy came to the AT world. They were originally part of a massive wad of gum that Bonnibel refers to as "the Mother Gum", and they eventually broke away from it and became their own seperate beings.
  • In The Adventures of Jimmy Neutron, Boy Genius, Carl Wheezer is targeted by what can only be described as a facehugger, and it impregnates him... in his butt. While Jimmy and Sheen are both disturbed by this, Carl and the other characters treat it as an Unusually Uninteresting Sight, and in the end, it's never shown how Carl gives birth to the alien; it just... appears.
  • Futurama
    • Amphibiosans (Kif's species) become receptive to DNA transfer when they develop a strong emotional bond with someone, their smizmar. DNA is then transferred through touch, and presumably any species' DNA is compatible. While in the episode in question the biological parentage gets mixed up, the smizmar is considered the "true" parent.
    • Dr. Zoidberg's species lay eggs in the ocean and then die off en masse. He's only lived so long because no female seeking a mate will even look at him. This doesn't prevent Zoidberg from having a Jewish Mother-equivalent relative, or introducing himself as "Norm and Sam and Sadie's boy." This is kind of Fridge Brilliance; since only the most disgusting and pathetic members of his race survive to raise the young, who do you think's going to be teaching them their standards?
    • Futurama plays with this trope a bit by having aliens be unaware of human reproduction. Human noses are harvested as an aphrodisiac under the incorrect assumption that the "human horn" is the main reproductive organ. Lrrr is surprised to discover that humans have a "lower horn" hidden in their pants.
    • Even the show's Mechanical Lifeforms have a bit of this going on. The main difference between the "ill-defined robot sexes" is that the male has an antenna which transmits information used to create a baby robot, while the female has an internal drive that receives the transmission. So far, so analogous, but everything about this process is treated as indistinguishable from the process it obviously resembles, which means that Bender having his antenna on the top of his head is exactly what it sounds like. (Females have antennae too, but without anatomical associations.)
  • There was an episode of X-Men: The Animated Series where Rogue was almost turned into a Queen for the Brood, an alien race which breed by basically infecting other species and turning them into one of themselves. However, Rogue touched Wolverine, borrowing his Healing Factor and returned to normal.
  • The French/Czech cartoon Fantastic Planet features the Draags. When the Draags wish to reproduce, they go into a meditative trance, which causes a spherical forcefield bubble to form around a small representation of themselves which then float up into the sky toward their planet's moon. Upon reaching the moon, they land on gigantic, headless Greco-Roman statues, which proceed to dance the waltz (no, really, that's all they do). In all fairness, that could have just been foreplay — the Oms (humans) did sort of start destroying the statues mid-dance. Also, despite the Draags exhibiting sexual dimorphism (there are Draags with breasts and ones without), all Draags form pink bubbles and land on the female statues. The male statues have blue bubbles which are stated as coming from some other species "from other galaxies". It's implied in one of the history lessons that there have been Draags for longer than there has been meditation, so the entire thing may really just be literally foreplay with aliens before they actually reproduce amongst themselves.
  • Human Resources (2022):
    • Addiction Angels have three penises, possibly to make them more attractive.
    • Hormone Monsters, a species that thrives on casual sex, have unisex wombs and can impregnate each other regardless of gender. Contraception entails just chanting "No baby, no baby, no baby" during climax to prevent getting pregnant.
  • The Glorzo of Rick and Morty are just the first two stages of the xenomorph cycle repeated ad infinitum. An egg hatches into a facehugger, the facehugger latches onto a host, it controls the host for a brief period of time, then the host lays an egg (dying in the process). Obviously, this is unsustainable, since there is no way to replenish the population after unplanned deaths (two die in an accident on-screen, kickstarting the plot), so, predictably, given the show, the entire species is almost extinct by the end of their debut episode.
  • The Mechanical Lifeforms of Transformers often have some "Bizarre Alien Assembly Process". Since Beast Wars they're usually depicted as metamorphosing from blank-faced liquid metal "protoforms," which depending on continuity may be grown in energy "wombs" and become fully grown cybertronians once they get sparks implanted. At least one series mentioned "protoform molds", which might be a jab at the old die-cast toys.
  • Steven Universe:
    • Gems are manufactured from non-living minerals using special machinery, with the new gems literally popping out of a hole in the ground. The Classroom Gems short "How Are Gems Made?" elaborates on this procedure: the Gems pop out fully grown, but the procedure also drains life from the soil and nearby plants and leaves the ground barren and withered. Viewed from the opposite direction, Rose Quartz found humans had bizarre reproduction methods, finding the idea of growing up so weird that she thought adult and child humans were different species.
    • While the conception of the eponymous Half-Human Hybrid probably had some conventionally human elements, there were some odder steps to get around his gem mother being from an artificial species that was never designed to sexually reproduce. She had to use shapeshifting to grow a womb, because she naturally has No Biological Sex, and find some way to pass on genetic information when she apparently had no DNA. Most importantly, since her Heart Drive is her real body, she had to pass it on to Steven, giving up the original form of her mind and body to become part of him.
    • The Watermelon Stevens reproduce exactly as one would expect... for watermelons. The young are grown in watermelon patches just outside the village, and are delivered to the adopting parents' door.
  • In one episode of SpongeBob SquarePants, SpongeBob demonstrates the ability to reproduce by budding—that is, smaller copies of himself sprout from his sides and eventually detach, just for a brief gag. Truth in Television, as this is one method in which real sea sponges reproduce. Spongebob still has two parents that look different than him, so apparently they can reproduce sexually too. This is also true of real life sponges, although most sponges are hermaphrodites.
  • The Secret Show: In "Alien Attack", the titular aliens' life-cycle relies on the humans eating them and then burping them up in order to be reborn.
  • Wakfu: The World of Twelve dragons lay eggs when they fall in love — no copulation or fertilisation happens. The egg hatches when it's ready. Also, Eliatropes (at least the important ones) have Born-Again Immortality and they come back to the egg alongside their dragon twin.

    Real Life 
  • Many of the above scenarios were based on the life cycles of Real Life organisms.
  • The males of numerous species of cephalopods (Squids, octopi, cuttlefish and nautiluses) utilise a specialised arm called a hectocotylus to store their gametes. When it comes time to mate, the male detaches this arm and gives it to the female, who uses the cells within to fertilise her eggs. While this process helps create life, Cephalopods are also semelparous; that is, they mate once in their life and then die. While the female dies of starvation, no longer hunting to guard the eggs with her life, the male typically dies after spending more time out in the open, where he's more likely to get caught by a predator.
  • Certain parasitic barnacles go through a ridiculous number of life stages, all radically different from another. Most notably, there is the ypsigon, a truly bizarre crustacean that resembles a barnacle larva and is superficially shrimp-like, but despite its common presence in seawater, the adult form has never been seen. Experiments in laboratories have attempted to force-metamorphose the y-cyprid stage using barnacle hormones, but instead of rooting itself in place and maturing into a sessile adult like a typical barnacle, the cyprid larva instead molted into essentially a slug, with no limbs, exoskeleton or digestive system of any sort and losing all resemblance to an arthropod. Unfortunately, all force-metamorphosed ypsigons die within days, so it still remains a mystery just what its final form would be like. Mind you, a typical parasitic barnacle won't look too different without a host (with one present, they tend to be similarly featureless tendril networks spread from legs to eyes included), so it's likely the host of this particular species is simply yet to be discovered.
  • Parasitoids are species with a strange life cycle that involves putting their offspring in (for endoparasitoids) or on (for ectoparasitoids) a host organism. Parasitoids are strictly dependent on the host to survive and reproduce (like a parasite) and (almost) inevitably kill it (like a predator, though predators need to eat more than one prey animal throughout their lives). An example are Ichneumon wasps, which typically use caterpillars as hosts. They inject their eggs into the hosts along with a polydnavirus that suppresses their immune systems to protect the eggs. The wasp larvae consume the least essential portions of the host's anatomy first, keeping it alive as long as possible. Once the larvae are mature, they emerge from the still living host and weave cocoons. Certain species produce mind-altering chemicals that causes the host caterpillar to guard and protect the cocoons until they hatch.
  • Eusocial insects have a reproductive caste (which makes up a small proportion of the group) and a sterile worker caste (which makes up the majority).
    • In honeybees, sex is usually determined by males being haploid (one set of chromosomes) and females being diploid (two sets of chromosomes, like humans). Female larvae fed royal jelly become the reproductive "queen" caste, otherwise they become workers.
    • In termites, all castes are split between male and female but, depending on the needs of the hive, can change caste. If any of the queens or kings in a colony dies, another will change to take their place.
    • Eusociality isn't limited to insects, either. Naked mole rats are eusocial mammals.
  • As mentioned above, some insect species have haploid males and diploid females. For them, a mature female can reproduce without mating. The resulting offspring are always male.
  • Prokaryotes physically merge when mating, in a process called bacterial conjugation. Mating also has little, if anything, to do with reproduction; they reproduce asexually. As a result, traits and genes can jump species and ever across kingdoms. This is why the non-eukaryotic parts of the evolutionary tree are more like a tangle of roots.
    • Not just the prokaryotic parts either; some major clades of protists, such as ciliates, likewise reproduce through cell division but exchange genetic information with one another independently of this.
  • Plants alternate generations. In the case of flowering plants, the equivalent would be a human becoming pregnant, then having sex which fertilizes their fetus, and then the fetus gives birth to the offspring.
    • A similar process can be seen in aphids, which alternate generations between parthenogenic females and sexual reproduction.
  • Jellyfish basically have sexual reproduction producing larvae, which then settle down as a polyp, which in turn buds and produces new medusae asexually, and the cycle begins anew. What's even weirder is that the medusae grow in a stack, with the top one breaking free from its siblings, one at a time.
  • Internal parasites, such as liver flukes, make all the above examples seem routine.
  • The male anglerfish is tiny compared to the female. The sole purpose of the male in life is that once he gets the scent of a female, he swims to her and bites down on the side of the female. At the same time he excretes an enzyme at the mouth which causes it to physically fuse to the side of the female, and his body starts to atrophy. With time he is functionally reduced to a pair of balls hanging from the side which the female can use to impregnate herself when it is most convenient. When anglerfish were first studied, the males were thought to be a completely different parasitic species. Some females even have multiple males fused into them.
  • Subverted with most polygamous birds; the actual process of reproduction for them is strange from a mammalian standpoint, but also pretty vanilla, being just them touching their genitals together (a process appropriately and adorably referred to as a "cloaca kiss"). However, the ways the male attracts the female to mate with him can be very weird. Temminck's tragopan, for example, has a bright blue wattle that he expands and starts flailing about whilst making clicking noises. The frigatebird has an inflatable red throat pouch that he blows up like a balloon before warbling loudly to females that fly over him. The buff-breasted sandpiper displays his armpit (wingpit?) to the females. And perhaps the strangest example, the ruff bird often attracts females by essentially having gay threesomes. Yep, an entire species of birds wherein the females think Guy on Guy Is Hot.
  • Because mating in water can be awkward if you have no grasping appendages and your spine isn't flexible enough to entwine around your partner, dolphins resort to Exotic Equipment to maintain a grip on their mates. Female dolphins' vaginal walls constrict to hold on, and males have a prehensile penis to cling to convolutions inside the birth canal. Both sexes occasionally use their genitals to grasp objects other than mates, Babylon 5-Centauri style: if you visit a Swim-With-Dolphins attraction, you can count on all the animals being females, because males have a bad habit of grabbing tourists' wrists or ankles with their you-know-whats.
  • Many polychaete worms follow a mating strategy called epitoky, where entire segments of the worm transform into reproductive organs, which then detach from the worm and seek out other such segment to mate. Sylldiae worms, however, take this a step further: their reproductive segments are fully mobile, and when they meet their counterparts, they friggin explode in a blast of egg/sperm cells.
  • Some invertebrates engage in a partly gruesome type of mating known, quite explicitly, as "traumatic insemination", where the male will stab the female with a blade-like penis rather than through the conventional hole. This is the method in which bedbugs reproduce, and is indeed quite harmful to the female, although it certainly discourages her from wanting to encounter other males soon.
  • Some species of fruit flies have poisonous semen, and after mating (which, similar to bedbugs, may be traumatic insemination), the female will be less likely to seek out and mate with other males.
  • In a few species of butterflies, the males will spray a pheromone on the female after mating with her that makes her smell like another male, so no other males will attempt to mate with her afterwards. This is actually beneficial for all parties, as repeated matings may disrupt the development of the eggs inside the female. In some other species, the male will just plug up the female's vent to prevent further mating from other males.
  • In some species of butterfly, the males will emerge from their cocoons before the females and upon finding a female almost ready to emerge, will mate with her the moment she's breaking through or while she's still inside the pupa by insertion through a cuticle (a process known as "pupal mating").
  • Neotrogla is a genus of cave-dwelling barklice in which the normal genitalia and typical animal gender roles are swapped between sexes: the males are choosier and the females are more aggressive with mating, and the females have penises and males have vaginas. The female mounts the male and uses her spiky penis (or technically, a gynosome) to scoop semen out of the male's genital chamber, a process which takes two to three days.
  • Many species of land-dwelling hermaphroditic gastropods have an organ known as a "dart sac", which contains arrow-like structures known as "love darts". Before two snails/slugs mate, they begin with a courtship dance that can last several hours and concludes with both parties attempting to spear their partner with a love dart. The dart is coated in a special mucus which increases sperm intake in the female sex organs, but are of considerable size (at up to three centimetres), and can be fired with such force it pierces right through the entire snail.
  • Most microorganisms have no gender and reproduce by splitting in two. The cells that make up any multicellular do the same for the organism to grow.
  • Scientists still know almost nothing about how eels reproduce. This is partly because eels change so much during their lifecycle that a single eel species may go through several phases that look like entirely different from each other and eels do not seem to develop reproductive organs until it is close to the time to use them. Eels in their earliest phase of life are only found in the Sargasso sea, so this probably means that eels, including species that normally are only found in freshwater, must travel a secret breeding location in the Sargasso sea that we haven't found yet. It wasn't even proven that adult eels migrate to the sargasso sea until late 2022 when scientists placed tracking tags on eels in Europe and observed movements. And to this day we still have never seen an eel egg.
  • Adactylidium is a type of mite which probably has the fastest (and possibly the most disturbing) mating cycle of any animal: the male mates with his sisters in the mother's womb. The baby mites then eat their way out of the mother and the process is repeated in four days. In some species, the male emerges from the mother alongside his sisters and then dies a few hours later, while in other species, he doesn't emerge at all, because his only purpose was to impregnate his unborn sisters (every brood contains one male and several females).
  • While not quite as extreme as Adactylidium, the common stoat has a very bizarre mating strategy for a mammal. While males sexually mature at about a year old, females are sexually mature at three weeks old, when they're still blind, deaf, and hairless, and the mother will let adult males mate with her female kits while they're still infants. Female stoats are able to retain sperm from mating for up to ten months later before fertilization and spend almost all their life pregnant.
  • Most amphibians fertilize their eggs externally. That is, the female lays a bunch of eggs in the water, and a male frog/newt/etc comes up and ejaculates onto them to make them fertile.
  • In at least one species of Corydoras (a common genus of small aquarium catfish), females will copulate by sucking the male's semen out of his vent with her mouth, having it travel through her digestive tract (a process which takes under five seconds), and then pooping the semen out and into a pouch formed by her pelvic fins where her eggs are held to fertilize them. It's suspected that the behaviour is widespread throughout the genus and this method may help prevent semen from being wasted by being washed away in the current.
  • Some species of velvet worm (a type of soft-bodied invertebrate resembling a cross between a centipede and a caterpillar) reproduce by having the male place a spermatophore on the female's skin, and then it melts through the skin into the body cavity. Even more weird is that (a) the female has a reproductive vent, so it's unknown why they perform insemination like this, (b) the spermatophore isn't corrosive, with the female velvet worm's body somehow sensing its presence and digesting the skin underneath the capsule and the outer shell of the capsule to let the sperm cells through, and (c) it's unclear how a self-inflicted injury doesn't harm the female.


Video Example(s):



Upon the human witnessing the Stiger knitting, she decides to transfur him, by releasing a giant egg sac that absorbs him and spits him out as a new Stiger.

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Main / BizarreAlienReproduction

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