Maybe the character was born a Mutant, or belong to a Human Subspecies, or have gone far enough up the Evolutionary Levels as part of the goal of evolution, or underwent extensive Bio-Augmentation of the essentially permanent kind... Or perhaps they were even created as an Artificial Human from the get-go. The bottom line is, this human character's biology, while not technically alien, cannot be considered "normal human" by any stretch of the term, be it due to having extra organs (duplicate or not), wildly different biochemistry, abnormal nutritional requirements, or even possessing completely new cellular organelles.
Compare and contrast to Our Humans Are Different, which is about all humans being significantly different than in real life.
- Italy's Idiot Hair in Axis Powers Hetalia is shown in the comic to be an "erogenous zone". It's unclear if the note was referring to his scalp reacting to the hair being pulled, or if he has actual feeling in the hair, but the fandom tends to run with the latter, and usually applies the same principle to the other curl-bearing nations. At least one fic goes to the logical extreme of the hairs being sensitive and has one bleed when severed. Also, Norway's curl actually floats around, detached from his head.
- Souther (or however you want to romanize it) in Fist of the North Star has situs invertus totalis (see Real Life section below) — which means that Kenshiro's first attempt to defeat him fails utterly. Because all of Souther's organs are inverted in his body, so are the pressure points that Kenshiro's Hokuto Shinken style relies on. When Kenshiro learns Souther's secret during their second battle, the Holy Emperor's fate is sealed.
- The titular Canaan has synesthesia, which translates as Aura Vision for her. One example has her seeing the bits of code needed to hack a door that a professional hacker couldn't get. Too bad that hacker was Alphard
- Hinted at in Free!, of all shows, with Rin Matsuoka. As a child he had Cute Little Fangs, but the prequel movie shows him with his signature shark teeth by puberty, implying that he either grew a third set of teeth (impossible for mammals, let alone humans) or they somehow became sharp. Oh, and he inherited the condition from his father, but his sister has normal teeth, implying it to be some sort of chromosomal mutation. Then again, this is a series where hair can be raspberry-red, blue, pink, or dark green...
- The title character from Skull-face Bookseller Honda-san can do the typical anime Sweat Drop and Blood from the Mouth, despite being a skeleton.
- The Ultimate Marvel version of Mr. Fantastic's body is an infinitely extensible fluid-filled sack containing, in place of an alimentary canal and other organs, just a squishable bolus of microbes that perform all metabolic functions. It's definitely Artistic License Biology, though fans chalk it up to Rule of Cool and leave it at that.
- Plastic Man is inorganic after his Origin Story; this actually makes him immune to Brainwashing, since his brain itself is apparently plastic.
- Post-Extremis, it was revealed that Tony Stark had managed to change how his insides were organized.
- Batman villain Killer Croc is allegedly a human who was born with a very rare skin disease, but many artists have started to make him less and less humanlike and more reptilian in appearance, sometimes having a crocodile snout and tail. One writer has Hand Waved this as being a mutation in his disease that grants him traits of more primitive animals.
- Mystique, Raven Darkholme is a shapeshifter. She has on occasions been shown able to rearrange her internal or grow a face on the back of her head, or even grow additional arms.
- Doctor Strange still looks human on the outside, but years of exposure to magic has taken its toll on him. He can no longer eat food that humans normally eat for one thing. Most of what he eats and drinks looks like it's from another dimension (and it probably is). Even worse, it tastes as bad as it looks — Stephen at one point complains that his meal tastes like leprosy. Still worse, Wong notes that even though that kind of food is the only kind Strange's body can accept, eating it will still eventually kill him.
- Batgirl's blood chemistry is so unusual that the government scientist ordered to analyze it thought he was being pranked. This despite the fact that, according to his analysis, she's entirely human from a genetic standpoint. The series never explains this, nor does it explain her seemingly superhuman prowess beyond a vague "gift" inherited from her mother, despite the before mentioned lack of any superhuman genetics.
- In ''Flat Tire with Bad Guys, Kenshin was revealed to have nucleated red blood cells which could take on the function of white blood cells in a pinch. In fact, any cell could take on any function, if need be. They can form new organs wherever and whenever they're needed. And Jack O'Neill's antigens. It's because he's a hanyou, and Youkai, in the Urban Legends universe, are a Human Subspecies created by the Ancients, whom Vathara envisions as Abusive Precursors.
- While Rei Ayanami is canonically known to be at least partially human, the specifics aren't made clear. To compensate, Fanfics tend to depict her with either this trope, Bizarre Alien Biology, or both, each in various ways. To list them all would be a herculean task, given the size of the fandom; one notably common issue, however, is whether or not she has an S2 Engine/Organ, and its exact role in her physiology.
- Diaries of a Madman: Navarone ends up as this due to various magical experiments. A backfiring spell results in him gaining pegasus wings, and an Emergency Transformation results in him gaining several plant-like characteristics.
- Peter Watts' The Things subverts this. The humans in the story are perfectly normal...which is utterly baffling to the alien. We can't shapeshift like all other life in the universe, we can't truly communicate beyond exchanging grunts, and our minds aren't disseminated throughout all our body cells but left coiled up inside cystic nerve fibers locked within bony cavities. To a creature that doesn't understand the concept of individuality, we're miserable, lonely, barely sapient tumors.
- In Mission's end, mission's beginning, about one in a thousand human males have a mutation referred to as Rutgers XY- the development of female reproductive organs alongside the typical (and functional) male equipment, theorised to have been deliberately introduced to the human genetic code during the Eugenics Wars to allow the supermen to breed with each other or themselves without having to involve inferior specimens. Not all males actually develop said organs fully, and those that do won't necessarily menstruate, but (as demonstrated by one James T. Kirk) that doesn't automatically mean they're infertile. It's still not as weird as some of the Bizarre Alien Biology from the franchise itself.
- Speaking of Mister Seahorse, there is the... concept of Omegaverse. More details can be found on that page, but the least Squicky explanation is this trope applied to Bizarre Alien Sexes.
- In the James Bond film The Man with the Golden Gun, the titular man with the golden gun is a Professional Killer named Scaramanga, who aside from using a golden gun and requesting a million dollars for every hit, is distinctively known for having a supernumerary nipple (see Real Life section). James Bond uses a prosthetic when posing as him to a man who has hired Scaramanga, but never met him.
- The Deathless Kings from Craft Sequence are undead human skeletons that can still eat, drink, and have sex.
- Human soldiers from Old Man's War have their brains downloaded into genetically engineered bodies that have green photosyntesizing skin, cat eyes and nano-bots instead of blood.
- In Alan Dean Foster's Tipping Point Trilogy, body modification has become basically as easy as getting a haircut. Power Perversion Potential is rampant.
- The Eighth Doctor Adventures novel The Blue Angel features an Alternate Reality Episode in which the Doctor is theoretically human. He has two hearts, no navel, and an unusual aversion to the cold. It's probably related to the fact that his mother is a mermaid.
- In the mystery story "The Image in the Mirror" by Dorothy L. Sayers, a key plot point is that one of the characters has situs inversus.
- Humans of the planet Covenant in Greg Egan's "Oceanic", who are descended from a group of transhumans who have since rejected The Singularity, are not described in too much detail, but the main feature that is different from actual humanity is that the male's penis is apparently detachable, and passes to the female during sex, at which point it is grafted onto the female, and the male grows a vagina.note Unfortunately for the readers, they find this out in the middle of a sex scene, with almost no forewarning, landing the characters straight into the Uncanny Valley.
- In The Bleeding Man, no one can figure out how the titular character keeps bleeding, or how to stop it.
- In Greg Egan's novel Distress, one Crazy Survivalist has loaded himself up with so much Bio-Augmentation to survive any possible apocalyptic scenario that he doesn't even have DNA in his cells anymore. He can also digest tire rubber in a pinch.
- Doctor Who: The Doctor's companions, as a result of exposure to the Time Vortex, are altered on a genetic level. Results include altered white blood cells and Ripple Effect-Proof Memory.
- The Sebeceans in Farscape are humans decended from Super Soldiers who were genetically engineered by aliens long ago. They have improved physical strength and eyesight (humans are apparently practically blind by the standards of other races) but fewer redundant organs and an extreme (seriously) weakness to high temperatures.
- Also, their women can delay pregnancy once an egg is fertilized (until such time as it is convenient to grow the baby), and pregnancy is accelerated once it is actually begun.
- Situs inversus turns up again in Orphan Black, where it's used as the explanation of how Helena survived being shot in the chest. Genetic chimerism later makes an appearance in Kendall Malone, whose two separate DNA profiles were duplicated to produce two lines of clones.
- The Zephryians in Son of Zorn are animated humans. They can mate with un-animated humans and have children. Male Zephryian humans have two penises, two scrotums and a man-womb.
- In Supernatural the Special Children develop psychic powers, the ability to kill with a touch, and super strength, after being fed demon blood as infants.
- Journey into Space: In The Red Planet and The World in Peril, the Martians altered the biology of many humans so that they could survive in the Martian atmosphere.
- Warhammer 40,000:
- Adeptus Astartes. To wit they have aside from the normal human organs 19 implanted organs: A secondary heart. An organ that increases bone structure and makes their ribcage bulletproof. note An organ that makes their muscles grow vastly larger and more powerful. An organ that increases their blood's clotting ability. An organ that allows them to only need 4 hours of sleep and can go for two weeks without any sleep at all. A pre-stomach that can neutralize otherwise poisonous or indigestible foods. An organ that allows them to "learn from eating". note A third lung that allows them to breathe in toxic atmospheres and underwater. An implant giving them far-superior vision to humans. An implant that makes them immune to motion sickness and the ability to consciously filter sounds. An implant that allows them to enter a healing coma/suspended animation. note An implant that controls the amount of melanin in their skin.note An organ that quickly filters the Marine's blood, rendering them immune to most poisons. note An organ that enhances a Space Marine's sense of taste to such a high degree that he can identify many common chemicals by taste alone, a Marine can even track down his target by taste. An implant that allows a Space Marine to sweat a substance that coats the skin and offers resistance to extreme heat and cold and can even provide some protection for the marine in a vacuum. An organ that allows the marine to spit a blinding contact poison, the poison is also corrosive and can even burn away strong metals given sufficient time. Implants that are the base for the the other organs. And finally an implant that allows a Space Marine to interface directly with his Power Armor. Many Black Library writers and 40K characters use the term "posthuman" to refer to Astartes for a reason.
- The Primarchs. All of the above? Derived from the Primarchs' genetic material. And they were created from the Emperor's genetic material. While the details of their biology remain unknown, the Primarchs' and the Emperor's superhuman abilities are signs that beneath the surface, their bodies were very different from the bodies of normal humans. A combination of this, his own psyker abilities, and the Golden Throne (which is falling into disrepair), are probably what's keeping the Emperor barely alive even though most of his body has rotted away after Horus tore him apart.
- The Primaris Marines engineered by Cawl have three additional organs. They have metal coils that reinforce their sinews to enhance strength, a brain implant that improves the performance of the other implants (which is actually half of the original God-Maker organ the Emperor used in the creation of the Primarchs — the plans for the other half were destroyed), and a heart implant that pumps the Primaris Marines full of stimulants when they are on the brink of death to jumpstart repair of bone, muscle, and tissue.
- In Parasite Eve, the protagonist Aya possesses a more benign/passive form of the "evolved" strain of mitochondria serving as the franchise' Big Bad, which are not only a self-aware Hive Mind that can hijack their "hosts" and act like The Virus, they possess actual superpowers, which include Spontaneous Human Combustion and Body Horror transformations!
- Common in Metal Gear:
- Metal Gear Solid 2: Fortune was born with her heart on the right side, due to situs inversus (see Real Life section).
- The Pain in Metal Gear Solid 3: Snake Eater uses weaponized bees as part of his quirk. One of these bee types are "bullet bees", which are bees which he grows within his body. He attacks with them by spitting them out like bullets at an enemy, which bore into their targets and eat their flesh from the inside out until they are removed.
- Quiet of Metal Gear Solid V: The Phantom Pain actually drinks and breathes through her skin. Which gives a bit of a justification for her running around on a battlefield practically naked. If she is completely submerged, however, she will drown just like a plant would, and although you can't use this against her in-game, she can also apparently be killed by being splashed in salt water.
- In the Enemy Within expansion for XCOM: Enemy Unknown, you can use "meld" to, much like the Astartes mentioned above, extensively modify your soldiers' bodies. You can give them chameleon skin, two hearts, regenerative bone marrow, leg muscles to allow them to jump like fleas, aim-correcting eyeballs; the list goes on and on...
- The people of Yharnam from Bloodborne end up turning into werewolves and monsters due to experimenting with alien blood they found deep in the catacombs under Yharnam. The fact that the people of Yharnam were so accepting with the drinking and injection of blood in the first place implies that the humans of this world are vampiric in nature.
- Similar to the Hetalia example above, Aoba from DRAMAtical Murder has hair with nerve endings in it. In his backstory, it's revealed that he was born attached to his twin brother from it.
- In Hell(p) some people get random non-human features after they die. Can be as small as a weird eye color or as big as an extra set of limbs, and anything in between. Also, everyone has a Wound That Will Not Heal which doesn't kill them, even though it's possible to die of physical trauma in this version of Hell.
- In Quantum Vibe when Seamus is originally introduced he has some physiological abnormalities due to a botched rejuvenation, gigantism combined with a metabolic disorder that made him morbidly obese, nerves in his hair, and the ability to fart at will. He had most of the problems fixed during the Luna arc, though he's still pretty tall.
- Alice Grove: Referenced in a conversation between Gavia (a Nanobot-enhanced cyborg) and Sedna (a Super Soldier with extensive modifications, including quantum entanglement with a black hole to let her violate the laws of thermodynamics):
Gavia: [Changes her skin colour with a thought] I lost my nanotech. I'm not baseline.
Sedna: Hey, preachin' to the choir, here. I can photosynthesize if I have to.
- In Ask White Pearl and Steven (almost!) anything, Steven is the Half-Human Hybrid son of Greg Universe and White Diamond. White Diamond was taller than the Crystal Gem's temple and her gem large enough to match. Because of this, Steven lacks a human brain, the majority of his mother's gem occupying the majority of his skull cavity and the pointed end of her gem visible as a small horn on his head.
- Ennui GO!: The SJW with his many buttholes, Noah's freakish elephant penis, and Jerry all come to mind.
- OZZY, the mutant Prince of Darkness. Medical Science had no explanation for why he hadn't drugged himself to death many times over. Medical Science decided to investigate. Medical Science found that Ozzy has several genes that allow him to metabolize opiates and alcohol far more efficiently than most humans. Caffeine? Not so much!
- Situs inversus, especially the totalis version, is a congenital human condition where the internal organs are in reverse of where they normally are (heart with apex on the right, liver on the left, etc.). Absent any actual congenital defects, such individuals can lead otherwise perfectly normal lives.
- Ironically, it's the milder versions of this condition that can be life-threatening, such as when a heart that's inverted in an otherwise-normal chest (a condition known as dextrocardia) tries to pump blood into the lungs with its stronger side and to the body with its weaker one, rather than the other way around.
- There are also quite a few other congenital birth disorders, from practically invisible (webbed fingers/toes), mostly harmless (cleft lip/palate, extra finger(s) or toe(s), alopecia (lack of hair)), debilitating (limb deformities), and probably not going to survive for long after birth, if the infant even lasts that long (born without most of the brain). Some people also have pointy ears, pointy teeth, or excess body hair, which makes them look like elves, vampires or werewolves, respectively.
- Less obvious examples would be the ability to see colours that are invisible to most of the population, have a better dark vision, or quirks like being able to keep one's own body temperature at a comfortable point, regardless of outside temperature.
- About 1/400 people has their kidneys fused into a horseshoe-shape, which is mostly asymptomatic. Mel Gibson is one notable carrier.
- HeLa is an immortal, single-celled organism with 82 chromosomes. It's a culture of cancers cells drawn from a patient (Henrietta Lacks) in the 1950s, which has continued to undergo cell division and grow, bizarrely unaffected by the Hayflick Limit, and at this point the number of such cells grown has easily surpassed the number of cells in the original donor's body.
- An... interesting and technically correct description of intercourse popped up in Something Awful (a middle-school teacher requested things to make her sex ed class memorable):
Tony Danza Claus: I really wanna teach a troll sex ed class. But stick to actual facts.
"The blood rushes into the penis, which is basically an elongated clitoris made of the same erectile tissue of the labia. Then the man puts his re-purposed clitoris into the vagina, which is lubricated by mucus, just like snot, and after so long the man ejaculates, which means a funny smelling liquid called semen, which comes from a gland in his asshole, mixes with some worm-like creatures and then comes out of where he pees."
"So sex is basically snot and blood and rear end gravy and worms all thrown into a big sweaty bowl that can result in a baby, which cost on average $28,000 a year. Any questions?"
- Anything can become this when you think about it the right way. The mouth for example? It's a hole in your skull lined with exposed bone (teeth), housing a exposed muscle that is detached at one end (tongue) that people touch with their exposed muscle for pleasure (kissing), and used to put various things inside you (food). Common examples are the heated-with-fire muscles of animals (cooked meat), flower heads (broccoli), the ejected and empty "womb" of a bird (eggs), and bug puke (honey).
- 7 Terrifying Things They Don't Tell You About Pregnancy
- 6 Real People With Mind Blowing Mutant Superpowers: a group of people who, through some random combination of strange physical quirks, have abilities that seem superhuman.
- Genetic chimerism in humans came to light when two new mothers — one in Massachusetts, the other in Washington State — gave birth to children whose initial DNA tests showed that the women's husbands were the biological fathers, but that they were not the biological mothers. Further tests showed that both mothers had two different DNA profiles in different parts of their bodies.
- Wisdom tooth extraction is an experience that is apparently universal to your average teenager or vicenarian. If they aren't getting them removed, then lucky them, they never grew them at all! And then there are those who never had them removed because they had so much room in their mouths that the wisdom teeth were able to grow in and settle in as happy and comfortably as any of the other teeth they grew. Some even have more than one set of wisdom teeth in there.
- Played With in the case of double-jointed people. They are not actually an example of this, but they sure do look like it when bending their limbs in odd directions.
- Some people who are double-jointed, less than 30%, also have issues with depressants(pain killers, anaesthesia etc.). This can take many forms but common ones are higher tolerances, increased rates of metabolism and even immunities.
- A supernumerary nipple is a third nipple that grows on the human body, with a rate of about 1 out of 18 males and 1 out of 50 females. They typically appear on the "milk line" of the human body, but have been known to develop as far away from the chest as a person's foot, and depending on the type are frequently mistaken for moles. Notable people who have supernumerary nipples include Lily Allen, Mark Wahlberg, and Zac Efron.
- Michael Lotito was famous for eating objects such as metal, glass, televisions, a bicycle, shopping carts, a coffin, and, over the course of two years, an entire Cessna 150. He also drank large amounts of mineral oil to help wash these things down. He didn't suffer any kind of health problems from his diet, although he did mention bananas and hard-boiled eggs made him sick.
- Synesthesia is likely another example (likely because science isn't completely sure what causes it, but it's probably biological). It's a sensory condition where two or more senses are connected, causing synesthetes to see sound, or taste words when they speak, for example. As it's something you need to be born with, many synesthetes don't realize that most people don't experience the world the way they do until they're older.
- In some people, hyperactivity can provide them with a seemingly superhuman level of energy as well as mildly retarding the visible signs of aging.