"Osamu Tezuka was educated as a doctor, so the stories are rich in medical knowledge and experience. Except, of course, when Tezuka decides that it would be more fun to just make crazy shit up. Which is pretty much constantly."
Acceptable Breaks from Real Life
The work contains things that are biologically impossible - often skirting the Critical Research Failure
level from the era the work was created in, except the biologically impossible things are needed
for the premise of the work, and the work is better for having them
characters would not be half as fun if they didn't sometimes do things that no truly normal person would be able to do. We are willing to handwave
the existence or seriousness of flesh wounds
if it means our favorite protagonist will still be able to do his stuff next week.
We can't have Fantastic Voyage Plots
or attacks of the fifty-foot whatevers
without breaking the Square/Cube Law
, and those types of stories can be fun. We can't have vampires or zombies without breaking a few rules of biology (there's no such thing as unbiology
If a show which normally has a naturalistic bent wants to deal with phenomena that are normally considered supernatural - say, telekinesis or mind-reading
- and treat the phenomena as real, they have to do this with a few dashes of technobabble
if they don't want to invoke Skepticism Failure
. If the hero is by nature a skeptic, then you do not
want to invoke Skepticism Failure
without a good reason.
We don't normally want radiation
to simply do what it does in real life
, unless you want a Downer Ending
before the work has had the chance to begin. We want genetic engineering to do things it isn't known to do in real life
, and we don't always want to wait a generation to see the effects. We sometimes want the fast action of a subtle Lamarck Was Right
We like the ease of identification Identical Grandsons
permit when Time Travel
Early on, such things get worked in by Rule of Cool
or Rule of Funny
if they aren't inherent in the premise
. At their height, it can become Reality Is Unrealistic
: even if the writers do know biology, they work things that would Fail Biology Forever in because the bulk of the demographic want the inaccuracy
of Rule of Cool
A Super Trope
to Funny Animal Anatomy
A Sister Trope
to Art Major Physics
Contrast: Hollywood Science
, Artistic License – Biology
, Dan Browned
open/close all folders
- Almost all modern examples of Nuclear Nasty, where it's clear they don't actually think radiation works that way (I.E. creating monsters) but are doing it merely for the sheer Rule of Cool.
- Likewise, practically every example of the Zombie Apocalypse genre requires that viewers ignore the issue of where the living dead get their capacity to move, if they lack a metabolism to generate energy and their tissues are so decayed that muscle contraction and neural signaling shouldn't be possible. Even variants in which the "zombies" are biologically alive tend to neglect things like the ravening hordes' need for water or rest.
Anime and Manga
- Osamu Tezuka, the author of Black Jack, was a qualified doctor but freely admitted to ignoring medical accuracy in the interest of telling a good story. For example, the title character was able to get an artificial daughter by grafting a highly differentiated teratoma to a synthetic frame. Also, in Phoenix: Sun, the protagonist is tortured by having the skin of his head replaced with the skin of a wolf and then left to die. Against all biological possibility, the graft takes hold, and he becomes a Petting Zoo Person who can talk to animals and spirits. Even more impossibly, by the end of the story, the wolf skin finally rots and falls off to reveal that his old human face has grown back under it.
- Franken Fran does this. The roots of the stories are usually based in reality, but then it gets tweaked until it will ruin your dreams for the next month. Given that the main character is a Cute Monster Girl and her sidekick is a cat with a human head, you have to give somewhere.
- In Detective Conan, one of the critical plot elements involves Apotoxin, which stated the Million-to-One Chance Fountain of Youth (and for the other 999,999, poison) acted by initiating an uncontrollable cascade of apoptosis. The apoptosis thing is true, when explained. Then there is the cure. Where does the 200% increase in mass come from?
- BioMeat: Yuki Fujisawa's whole plot is solely made possible thanks to the basic design of the Extreme Omnivore mouths on legs, which defy any understanding of any digestive system, not to mention their creators' common sense. The American version uses slightly more common sense, but still circumvents all current biology courses.
- The bloodline powers in Naruto being part of people's DNA is just a justification for people having powerful abilities that no one else can copy. When a dude pulls out his own spine to use a Whip Sword we have officially thrown all laws of biology out the window. For that matter, any of the result of Orochimaru's experiments and surgeries: you should not be able to move your arms if you have high-powered air tubes running through them, surgery cannot let a human sweat silk that turns rock-hard, and an enzyme should not let you turn body parts into weapons and a jetpack, but Zaku, Kidomaru, and Jugo wouldn't be anywhere near as interesting if they couldn't.
- In Monster, at one point, a prostitute who has been shot in the gut (one of the most lethal ways to take a bullet) walks to a dingy clinic, where Dr. Tenma, trained as a neurosurgeon and without a full complement of medical implements, with only an untrained "nurse" to assist him, operates on her injured spleen. And she survives. And that's just one of the more implausible ones. Urasawa told a good story, but he definitely took some Artistic License with his medicine.
- The entire premise of Sex Pistols manga. It makes no sense, it's not meant to make sense, and if you think about it too much you find yourself wanting to dose yourself on large amounts of LCD + Laudanum, but it makes every plot point absolutely frigging hilarious. It's strange 'cause it's a BL manga, but it has that sweet mixture of 'awww' and 'really funny' that makes it work. To make things worse, men can get men pregnant, women can get women pregnant, and selling your DNA is a perfectly reasonable practice. You can pretty much imagine some really really fucked up family trees
- Toriko thrives on this trope. A gigantic mammoth that the heroes go spelunking inside, searching for the most delicious piece of meat. An overabundance of large predators eating each other. Flowers that detect how Badass you are. A guy with a skeleton consisting of 4000 bones. Then there are all the absurd food ingredients. The anime is even worse than the manga, having animals that are biologically impossible as well as environments that don't make one lick of sense.
- The manga of Toriko at least tries to explain why the animals are the way they are and how they can grow. The anime on the other hand? Its due to the fan submissions which are adapted every week for the new episode, and since the fans in Japan are children its a bit forgivable on how they are biologically impossible: children don't know that.
- Neon Genesis Evangelion has the bio-mechanical Evangelion, which in real life would not be able to stand up thanks to their legs being too slender. There are a lot of weird biological phenomena occurring in Evangelion (like an Angel's egg being incubated inside a volcano) that are explained via incomprehensible pseudo-science.
- Junji Ito likes this, and it can be found in nearly all of his stories. A Doll's Hellish Burial is particularly notable for being rife with it, despite being less than ten pages long.
- In Science Ninja Team Gatchaman, there is an episode generally referred to among fans as 'The Puppy Episode' (#20). In it, G-2 receives a hit that leaves a bit of shrapnel in his head -in an inoperable location. The good Doctor who is the Xavier for the team -and who is repeatedly shown not to be a medical doctor, but a scientist- decides that the only way to get the shrapnel out is to stick G-2 in a giant centrifuge normally used for G-forces training. G-2 later escapes and joins his team on the Godphoenix. The final explosion and death throes of the giant mole mecha (yes, really) send the ship into a massive series of spins -which removes the shrapnel. Somehow.
- The puppy of the fan title was rescued by G-2, resulting in his injury. The set-up was to show him as a softer character then the hard revenge-driven type he had so far been shown to be -but how drastically they fail in how medicine really works overshadows the moment of heartwarming.
- Attack on Titan's, uh, Titans should be far too heavy to support their own weight, much like the Evangelions above. This actually gets lampshaded by Hange, who has also discovered that severed chunks of Titans are impossibly lightweight—they appear to have plenty of mass while they're stomping around munching on people. The explanation for all this is still unknown. Then there is them wanting to eat people, yet not for food (their energy source is implied to be the sun). They just like to.
- Works from the Northern Renaissance (Flanders, in particular) tended to play this trope. Figures would appear slightly larger than they would in real life or a table would be tilted at an impossible angle so we can see everything on it. It's simply the whole of the forms themselves that are messed with, the details are still impeccable and true to life, as was typical of the detailed realism of this time period. It should be noted that Northern Europe Renaissance artists at the time did not know about perspective system which initiated from Italy.
- A well-known example is the Grande Odalisque by Jean-Auguste-Dominique Ingres which features a naked female slave seen from behind. Critics observed that the figures must have had five vertebrae too many to look this way.
- Psh, if you want to talk about stretching biology in art, go look at Mannerism. The proportions on figures are distorted and stretched all over the place. The church actually cracked down on this style of art because it was considered too weird at the time, and promoted the Baroque style instead.
- In another example of distorted figures, the Plaza Oriente is lined with statues with crude features and odd proportions. They were commissioned for placement on the upper level of the Royal Palace, and were thus designed to be viewed from below and from a distance.
- The Cubist and Surrealist movements both made heavy use of this trope, with Picasso and Dali being two of the most well-known examples.
- Sort-of case: Two artists (one of them being John Howe, medieval armor enthusiast) working on The Lord of the Rings would constantly tease and nitpick each other on their respective shortcomings in biology and armor design: "Your creature shouldn't be able to move, let alone fly!" "Well, anyone wearing that armor wouldn't be able to move either!"
- The X-Men are all "mutants" because of one gene being wonky, resulting in powers ranging from time travel to control over the electromagnetic spectrum to worldwide weather patterns modification. Initially the cause was just unspecified "mutation". The "it's one x-gene" explanation is actually an attempt to clean up the art-major nature of the biology since random mutations being that outright beneficial that many times is statistically impossible. Current issues have been attempting to clean it up further as popular understanding of evolution has increased; usually the explanation nowadays is that it's a gene that evolved the normal way (with some alien help) that is just switched off in most people, with the "mutation" being the flipping of the switch. By implication mutants all have the same altered genetics, it's just that the general "alter reality" ability manifests differently based on cheap clichéd childhood trauma.
- Booga from Tank Girl. In the movie, he's a kangaroo-man ultimate fighting machine bioengineered thing... made from a dog? The comic doesn't even bother justifying why he exists. At least it makes more sense that Tank Girl having a Half-Human Hybrid baby with her tank.
- The new origin that Alan Moore devised for Swamp Thing after taking over fulfilled three purposes. It allowed Moore to account for the character still being alive after being filled with ammunition. It put a new spin on the character — it was now a plant given human form rather than a human turned into plant. And it was freaky cool. It was also based on a theory that had been disproven shortly after the claim was first made, but Moore wasn't working for research grants.
- The story "La Nuova Razza" from the fumetti Terror Blu is about sperm that are super-intelligent, can TAKE OVER YOUR MIND by slipping into your brain(?!), are the size of tadpoles, have eyes and mouths (with teeth!), devour human flesh, and — wait for it — SEXUALLY REPRODUCE. Someone should have used a condom.
- The Kingpin. 2% body fat, 350 pounds of muscle. Can beat superheroes in hand-to-hand combat. AND IS COMPLETELY "NORMAL". He's not a mutant, there is no Applied Phlebotinum, there's no magic...just another Charles Atlas Superpower. He can CRUSH a man's SKULL with his entirely "normal" HAND. But damn if it isn't a cool version of Stout Strength.
- If Giant Man were to actually grow to his full size, he'd be unable to move and all his bones would be crushed to powder. By an elementary equation.
- The Teenage Mutant Ninja Turtles have essentially had the bodyform and biological processes of a peak human written into their DNA. For instance, they sweat, have a humanlike heat signature, walk upright, can metabolize human food, have thumbs...
- Alien: The creatures are so cool, it's easy to overlook the impossibility of the fast growth cycles (even before being sped up in the Alien vs. Predator movies) no matter how much it ate in that time, the fact that a creature outside of Earth is compatible with species from Earth even as a parasite, that silicon-based lifeforms aren't actually likely due to how silicon bonds, and how blood like that can work. Basically these things are powered by Rule of Cool and Rule of Scary.
- The Thing (1982): This and Rule of Scary.
- Although there is no official explanation given as to the how the Rage virus in 28 Days Later works after infecting a victim, the virus apparently infects its host after a single heartbeat. Also, the infected don't eat, they don't drink, it's debatable whether or not they sleep, and they're constantly vomiting copious amounts of their own blood. How could they possibly live for a total of 28 days before falling over dead from starvation?
- From Bee Movie:
- Let's start with a massive case of Insect Gender Bender — male worker bees. Also, bloodsucking male mosquitoes appear. Lots of them.
- Then the whole process of honeymaking (which in Real Life involves bees vomiting nectar back and forth into each others' stomachs) is depicted as a fantasy Willy Wonka-esque process. Bad, but not critical.
- Then one bee stings a man.. and survives by putting a plastic toy knife where its stinger used to be. Real bees that lose their stingers when they sting lose their internal organs at the same time — that's why it's fatal.
- They revive dead plants through pollination, which is akin to bringing someone back to life by having sex with the corpse.
- In Crank, the main character is given a drug that stops his adrenaline from flowing. This could work. Two problems: in Real Life, he would have died within seconds (this would have left the movie about the length of a film trailer). Also, fear is the most effective way to produce adrenaline.
- Face/Off features Sean Archer becoming Castor Troy and vice-versa through face transplant. Apparently we are supposed to forget that John Travolta (Archer) is 2" (5cm) taller than Nicholas Cage (Castor), or that their hairstyles do not match (for Archer, Travolta's buzz cut is modified by use of a haircut to match Cage's, but we never know about the reverse, other than potential use of styling gel). Don't ask how muscles, nerves, and blood vessels are connected so well that facial expressions are never compromised on either Archer or Castor afterwards. Or how the surgery leaves zero scarring. Or how the surgery is reversed for Archer in the ending after Castor's death.
- Godzilla is a prime example of this trope. It's best not to think too hard about how a giant radioactive dinosaur, giant butterfly, or half-plant half-Godzilla hybrid is able to exist. Just invoke the Rule of Cool, a bit of Techno Babble, and perhaps the Anthropic Principle (you can't have Godzilla films without Godzilla) and be done with it. ''This page attempts to scientifically explain how Kaiju could possibly exist. To summarize, they're basically reanimated corpses whose cells have been transformed into microscopic fission reactors.
- The 'farm humans for energy' backstory from The Matrix makes less than no sense. One much better solution for the machines would be to simply burn the humans and whatever they were feeding humans with. Humans were originally supposed to be organic computer hardware for the machines, which is at least somewhat plausible. However, the Wachowski Brothers were told to change that since the execs were worried people wouldn't understand it.
- A black & white horror movie called Monster on the Campus has the protagonist inject himself with a Coelacanth's blood in order to become a caveman. It's the "evolution" take on Jekyll & Hyde.
- The Species movies, especially the second one. A film about the difficulties Natasha Henstridge has getting laid...
- The fate of The Virus-infected astronaut's human victims in Species II: his Evil Spawn go from conception to full term in minutes and then tear their way out of their hosts like chest bursters. This is ridiculous because, whatever alien biology the fetus has, it needs nutrients from its human mother to survive; the human uterus could never supply enough to allow such growth rates. These things need to assimilate as much as nine pounds of material in minutes; even Alien chest bursters usually had the decency to take a couple of hours. Then there's the part where the infected astronaut blew off his own head with a shotgun and not only survived but also retained his memories, which is like smashing your hard drive, getting a new one, and expecting your old files to still be there when you plug it in.
- In The Happening, the scene with the man feeding himself to the lions was a great moment of unintentional comedy. In the scene, a lion bites the victim's hand and lightly, almost playfully, tugs the man's arm, ripping it easily out of the socket. The victim remains standing. In real life, the force required to wrench an arm out of a socket would have pulled the man to the ground. Even then, the joint would only be dislocated, the force required to tear muscle, skin and ligament is even more incredible. Apparently, this unfortunate man was made from papier mache. Of course, this is not getting into plants develop the ability to secrete a neurotoxin that makes people kill themselves. All at once. Without anyone realizing. And it's stopped by The Power of Love. This is all risible; unfortunately, it's also all plot-critical. Of course, one wonders why a highly effective predator decides to slowly dismember a large, live, moving prey - the most effective tactic would be to, well, kill it by suffocation first. After all, a lion could not know that a man wants to get killed by it.
- Another film with risible but plot-critical errors: Jaws: The Revenge. Most glaring is how the shark decides to kill a family out of revenge, even though the very concept of revenge is well beyond the mental capacity of a shark. (Or is it?..... Other fish do seem to have this concept) Also, this shark died in the original Jaws but apparently got better. How would it recognize relatives of Martin Brody, anyway? It also is able to travel from Martha's Vinyard to the Bahamas (which is too warm for great whites) in three days. And it roars. And leaps into the air. And it roars.
- The Bahamas isn't actually too warm for great whites. As endotherms they can tolerate a wide range of temperatures.
- Junior: To demonstrate that a newly improved fertility drug works, it is decided to test it on Arnold Schwarzenegger. Hey, if it works for a man, then it should definitely work for a woman! Though we never see this one used on a female. Since males don't have wombs, Arnie's character has to carry the child somewhere in his stomach cavity... and man, that is one effective fertility drug...
- Lampshaded in Rio:
Blu: I'm sweating. I didn't even think that was biologically possible, but look!
Lifts a wing to reveal dark 'armpits'
- There has never, ever been an actual self-colored red cat, as a few of the characters in The Aristocats are. This is genetically impossible due to red fur being linked to tabby stripes. There are two red coat patterns that could be mistaken for self reds: a diluted red, or cream, can have tabby stripes that are very faint and easy to look over, especially from a distance. A long haired red tabby might also be mistaken for a self red because the fur length can confuse the pattern. Neither of these shows up, as Thomas O' Malley and the orange kitten Toulouse are a vivid red and, as far as one can tell, do not have very long fur.
- Rise of the Planet of the Apes depicts apes both speaking human languages and throwing makeshift spears with accuracy and distance, something apes are physically incapable of doing due to different structures of vocal cords and skeletons respectively. Of course, this is Hand Waved by the ALZ-113 miracle drug changing the apes physically as well as mentally.
- Stephen King's Firestarter has pyrokinesis, telekinesis, mind controlling, and other things. All caused by a drug that was administered to several volunteers in their college years. King himself admitted the inaccuracy of this and says this is the reason he tends to avoid going into scientific explanations behind the plot devices of his later books. Of course one of his latest books use the damn ten percent thing.
- Hothouse by Brian Aldiss. It has giant insects, man-eating plants, people growing wings after being mutated by space radiation, the entire planet being covered by a single banyan tree, and giant plant-spider hybrids that use their webs to connect the Earth to the Moon. The publisher even admitted that he knew it was ridiculously unrealistic, but still published it because it was awesome. Which turned out to be good move, because it ended up winning a Hugo award.
- The Shel Silverstein poem "I'm Being Eaten by a Boa Constrictor" which has also been adapted as a song. It confuses boas with pythons (boas are too small to eat anything bigger than a rabbit). And the song has the protagonist eaten feet first. Granted, if they'd been eaten head first — the way boas normally swallow their prey — the poem would have been much shorter.
- The Zombie Survival Guide actually revels in this trope, describing the physiological changes undergone by a human who's infected with Solanum. If you disregard the fact that it's talking about freakin' zombies, and the occasional error about living biology (e.g. the 90% of Your Brain trope), it's not too different from many real pamphlets on medical conditions.
- Vurt is big on fives. So it has Five Races, five two-way mixes, five three-way mixes, and five four-way mixes, plus one purely theoretical combination of all five races. This means that some two-way mixes can breed with partners that one of their parents couldn't breed with, which is genetically improbable—but since one of the viable pairings is human and dog, it's also probable that They Just Didn't Care.
- Colin O'Boyle's The Chronicles of Professor Jack Baling has a type of insect that lives in paralyzing gel, a St. Bernard-sized mantis shrimp that walks on land and serves as the living machine for a hyperintelligent cuttlefish named “Gwendolyn,” and that’s just from the first two episodes.
- In A Song of Ice and Fire, the laws of genetics are expressly (by Word of God) not identical to Earthly genetics. In general, a kid will take after the looks and genetic traits of one parent or the other, but a key plot point is that the Baratheon seed is strong and will always overwhelm the other party's bloodline. Neither of Robert Baratheon's sons resemble him at all.
- Maggie Stiefvater's Shiver werewolf series has a rather... odd explanation for werewolf transformation. Once you're bitten, the transformation into a full-blown wolf is triggered by cold temperatures. (Living in a hot climate to stop this has no effect, since even a sudden blast of air conditioning can kick off the transformation.) But it's not this. In one of the books, one of the characters has not taken well to being bitten, and it is then discovered that perhaps bacterial meningitis could stop the transformation, seeing as breaking out into a fever pre-transformation almost cured one of the characters. So yeah... injecting somebody with bacterial meningitis somehow helps rather than hinders.
- The robustness of zombies is portrayed inconsistently in World War Z. In some parts of the story zombies' limbs detach quite easily. In others zombies walk along the ocean floor at crush depth with impunity. High explosives which should liquify corpses are ineffective because "they don't cause headshots," yet if zombies have the hardiness portrayed elsewhere it's surprising a bullet can get through the skull to the brain at all. Also, there's more to using a body than just having a working brain. A shredded muscle will not function - forget pain tolerance, it just won't respond. Characters either lampshade this by pointing out how none of this makes sense, or handwave it by saying zombies don't follow the laws of nature, and Brooks has said he purposefully took artistic license with these tropes.
- Three of the bratty kids' fates in Charlie and the Chocolate Factory invoke this trope:
- Augustus Gloop's journey through a tight pipe leaves the Fat Bastard squeezed skinny.
- Violet Beauregarde is transformed into a giant blueberry via three-course-meal gum and has to have the juice squeezed out of her to be returned to Not Quite Back to Normal, in that her skin and hair remains blue. In the 2005 film adaptation being squeezed also leaves her absurdly flexible. In the 2013 musical, she explodes as a result of the transformation but apparently can be put back together — provided she hasn't started to ferment — and, again, be at least Not Quite Back to Normal! (This version also claims her transformation is the result of the gum creating "excess fructose in the fluid sacs".)
- Mike Teavee, shrunk to an inch or so tall, is stretched out to restore his original height and prescribed Supervitamin Candy to quickly fatten him up so he won't be a paper person. He gets overstretched and becomes ten feet tall!
Live Action TV
- Between the various undead, the injuries people live through and Giles' lack of brain damage from all the times he gets knocked out, Buffy the Vampire Slayer loves this trope. And that's not mentioning Giant Dawn in S8.
- Farscape is a prime example of this. The most blatant example would probably be a digestive system that somehow manufactures helium. Since most of it is happening to aliens, though, it's a little easier to accept.
- The entire premise behind Out of Jimmy's Head is a brain transplant. But they managed to save the "Personality Gland" to handwave why Jimmy is not acting like Milt, since everything that makes a person is in the brain.
- Heroes: Evolution does not work that way (see the X-Men entry above for why).
- The short-lived series Threshold has 'hyperdimensional radiation' that was capable of changing human DNA to a triple helix as part of a "xenoforming" plan. The show was never too bothered about scientific accuracy but it did have Data and a sex-crazed midget.
- In a Battlestar Galactica episode (season 2, episode 13), Dr. Baltar heals president Roslin's cancer by injecting her with some cylon/human hybrid blood that is more resistant to diseases because it has no antigens (particles that are recognized as hostile by the immune system) and therefore "no blood type". Therefore, it is somehow capable of destroying a cancer in a very late stage. If Type O negative blood (the real type closest to having "no antigens") could do that, there would be a lot less cancer in the world...
- Doctor Who
- The Weeping Angels, reveling in this and Rule of Scary, literally turn to stone when you look at them. Biology does not work that way, and neither does quantum physics, but you'll be too busy crapping yourself to notice.
- The Ood carry their brains in their hands. No, there is nothing to protect their 'hand-brains' in case the Ood accidentally drop them or slip on the frozen surface of their home world. This species design is possible, but the designer of the Ood seems to have forgotten that evolution is not so kind to people born with their brains unprotected.
- In the Community episode "Epidemiology" the physician agreeing with Annie's plan to lower the temperature in order to "break the fever and kill the virus". Breaking a fever is all well and good for preventing brain damage, but the fever is the body's defensive response against the virus which was spread among people with presumably normal 98.6 degree temperatures. Bringing them back down to those temperatures they had when the virus was spread in the first place would do nothing against the virus itself, whatever brain damage lowering the temperatures was preventing notwithstanding. The thermostat needs to go at least below 50 F to affect the environment of the virus, by causing hypothermia in its host (it could possibly show up in Pierce and Lenard a bit earlier). And these low temperatures would just be expected to (very slightly) slow the spreading of the virus in the body, not "kill" it (it's pretty hard to kill something that isn't especially alive in the first place). The average virus would still be active, much less capable of reactivation, long, long after the human has died of hypothermia. There is a reason fevers and sterilization techniques use high temperatures, not low ones.
- Warhammer 40,000: Space marines, just (acid spitting, one-ribbed, three-lunged, two-hearted, two-stomached, electric skinned, super strength, reinforced skeleton, fast healing, power armored) space marines.
- A couple of editions back, there was a line about Orks having an "algae base" twined around the double helix of their normal DNA. This is, um, exactly nothing like how DNA works in the real world. This line has since been retconned out and replaced with "animal and plant symbiosis" to explain why Orks are green and really hard to kill, which is a bit more plausible and doesn't require a tertiary strand that somehow knows it's algae.
- Other genetic weirdness: Eldar apparently have triple helix DNA. No-one's entirely sure how this would work; it does exist, but it's not all that stable, making it less than ideal for information carrying. Eldar are explicitly a product of genetic engineering by a Sufficiently Advanced Alien race.
- Deadlands includes a little line in the monster books that tells the Marshal to flat out ignore real world science when making monsters, biology being the one ignored the most. It's justified in that all the monsters are born of people's nightmares-so long as it's scary, make it.
- Mad Scientists can also invoke this trope with their creations-so long as it sounds plausible, it's a go. The book states that since most players are not expert scientists, this trope (and several other ones) are not just allowed, but required.
- Meanwhile, some high-level Librarians in the Post Apocalyptic Hell on Earth setting can weaponize this trope: by loudly decreeing the physical impossibility of the Abominations around them, they can force them to take serious damage and possibly cease existing. (This can be one of the game's most efficient ways to deal with hordes of very large monsters.)
- In Homestuck, the Trolls get this a lot. For starters, the hemospectrum. Different Trolls have different blood colors, affecting their social standing. Those lower on the hemospectrum (reds, oranges, and yellows) are more likely to have psychic powers, while those higher up (blues and purples) are more resistant, and this higher up live longer by centuries. Also their horns are completely different shapes, generally somewhat impossible without body modification (Think Eridan). For the kids, their eye colors. Dave has blood red, Rose and Roxy have pink, and Dirk has orange.
- The Whateley Universe. In spades, for the same reason as X-men above. Impossible superhero/supervillain powers? Got 'em. Zombies? The Necromancer's certainly got 'em. Werewolves? At least four different kinds. The only thing they don't have is a giant humanoid robot. Okay, they do have it, but the devisers can't get it to walk because of the Square/Cube Law and such.
- At one point in the fanfic Shinji And Warhammer 40 K, Shinji is required to go through a temple of trials. He invokes this trope during a rant about the trials, complaining that the giant scorpions he encountered shouldn't be able to support their own weight.
- Darwins Soldiers has some of this. X-Men like powers and Hollywood Healing are the most common offenders. Granted, the X-Men styled powers are treated a little more realistically (i.e. it is not one gene but multiple genes that determine the power, organisms have to be created with the powers, etc.).
- The Global Guardians PBEM Universe featured this. It advertised itself as an "open source superpowered roleplaying universe", which meant that pretty much any explanation for superpowers was useable. Bizarre alien biology as the source of superpowers, not to mention the "mutant" thing, all saw a lot of use.
- Lampshaded in the My Little Pony: Friendship Is Magic episode "Baby Cakes," where the Cakes, both earth ponies, have twins who are a pegasus and a unicorn. Mr. Cake explains that he and his wife have very distant relatives of those species, one of which would have required the genes to move back a generation, and nervously says "That makes sense, right?"
- This also might be a case of Getting Crap Past the Radar, when you think about it.
- More innocently, it could be an affect of the magic present in the universe, permitting massive but exact mutations.
- It could work as far as the FIM universe goes, pegasi, unicorns and earth ponies are all types of equine so should theoretically be able to interbreed, and if somewhere in the Cake family history a pegasus and a unicorn married into the family, their genes could potentially be passed down to show up in later generations, and while rare, "throwbacks" do occur occasionally.