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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.

The trope can come into two flavours:

  • Standard: These are fictitious in principle, and thus typically the domain of Speculative Fiction.
  • Truth in Television: some of the detailed aspects of our biology can be downright bizarre to us, even if they technically make sense. Additionally, there are real-life medical conditions that technically result in abnormalities to an otherwise healthy human biology (see Real Life section).

Note that not all cases of Human Subspecies, Transhumanism, Mutants, Bio Augmentation, etc. lead to Bizarre Human Biology. They are only possible ways for attaining this trope.

Compare and contrast Bizarre Alien Biology, which may overlap with this trope in cases of Half Human Hybrids or Panspermia.

Examples (Standard flavor)

Anime And Manga

  • 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. On a creepier note, 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.

Comic Books

  • 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. Yes, we know; Fails Biology Forever. Chalk it up to Rule of Cool and leave it at that.
  • Plastic Man is literally 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.

Fan Work

  • 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.


  • Star Wars: Humans, as well as all other living species in The Verse, possess "midi-chlorians," mysterious organelles which have some intricate connection to the Force.


Live-action TV

  • 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.


Tabletop Games

Video Games

Examples (Truth in Television flavor)



  • 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.

Video Games

Real Life

  • 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.
    • There are also quite a few other congenital birth disorders, from mostly harmless (hare lip, extra finger(s) or toe(s)), 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).
  • 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 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."

  • 7 Terrifying Things They Don't Tell You About Pregnancy
  • Does chimerism count? 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.
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