The Scariest Genre of Science Fiction

If I were to ask you ‘what is the scariest type of science fiction?’ you probably wouldn’t say ‘Evolutionary Horror.’ …Mainly because it’s a name I came up with for this video, but also because it doesn’t sound particularly frightening. Evolution isn’t scary… or is it? Twisting through the history of sci-fi is a hidden subgenre that derives terror from the altered self — from the uncanny dread of a force beyond our control evolving the human into the inhuman. So, for this entry into the archive,

we’ll uncover the terrors of this category, and dive into the type of sci-fi that I find the most fear-provoking of all… “I have no mouth… and I must scream.” That was the voice of author Harlan Ellison, reading from his 1967 short story of the same name. It is one of the most unpleasant works of fiction ever written, yet foundational to not just to sci-fi, but to the evolutionary horror subgenre. In the narrative, the last five humans on Earth are held within a vast underground labyrinth being

eternally tormented by an artificial intelligence called “AM.” Originally a Cold War supercomputer, AM gained sentience but found it was entombed within millions of miles of circuits and wire that made up its infrastructure, forever unable to move. Seeking revenge, it annihilated planet Earth — for unlike most evil AI in fiction, AM isn’t rational but spiteful, filled with ceaseless hate for the creatures who made it. AM’s true, final revenge is altering the five survivors. One of them is turne

d into a kind of early simian with twisted limbs, incapable of rational thought. All are unable to die from old age — an adaptation that would once have been considered a blessing, but is now a nightmarish curse. At the end of the story, the narrator is transmuted into an amorphous blob, unable to interact with the world or express their anguish — hence the title. …I wouldn’t necessarily say that I like this story. I don’t think it’s meant to be liked — or even understood. The notoriously irrita

ble author rejected pretty much all interpretations of his writing throughout his life. But if we were to try and comprehend why the story is so unsettling, I can’t think of a better point of comparison than All Tomorrows. Written and illustrated by channel mainstay C. M. Kosemen, All Tomorrows tells of humanity’s encounter with the Qu — a hostile alien species that, like AM, genetically alters humanity into a myriad of unrecognizable forms for seemingly no reason other than their own amusement.

The series has inspired incredible fan works by artists like Tomasz Woźniakowski that translate the images into tangible, CGI animations — which help you more acutely feel the suffering of these altered humanoids. One unfortunate group, the Lopsiders, are flattened out as if by a rolling pin and made to crawl across the surface of a high-gravity planet for millions of years. The Temptors are turned into beaked cones of flesh rooted into the soil like grotesque plants. Perhaps the most tragic of

all are the Mantelopes — creatures with full human minds in the bodies of grazing animals. Left to fend for themselves upon the Qu’s sudden disappearance, these beings live agonizing lives, able to see and understand the world around them but helpless to change it. The book describes mournful herds roaming across the plains for centuries, singing songs of desperation and loss… (Mantelope Calls) Perhaps mercifully, the selective forces of evolution make their agony a short one, as more instinctu

al, animalistic Mantelope prove to be better grazers. In a grim reminder that the human mind isn’t sacred to the evolutionary process, the herds soon fall into contented silence — forgetting all they once were. Beyond the horror, there’s a quiet, unplaceable sadness at play here. All Tommorrows and I Have No Mouth are uncomfortable reminders of humanity’s fragility — extracting terror from the fact that evolution made us, and could erase us just as easily. Few things are more intrinsically distu

rbing than something — be it AM or the Qu — changing us so completely we forget how to be human. But what about a story where this alteration is self-inflicted? Altered States is an often-overlooked movie about a scientist who uses a sensory deprivation tank in combination with psychoactive substances to accelerate and regress evolutionarily. Renowned critic Roger Ebert described it as a film that “hurls its characters headlong through billions of years [of evolution] and finds nothing except an

anguished scream.” I… think I get what he means. Over the course of the film, the lead scientist melts into a primordial soup, reverts into a caveman like creature and goes on a midnight rampage, and even becomes an amorphous mass of consciousness that transcends reality. It’s… a whole lot. Not all the visuals have aged flawlessly: it’s a movie, like the culture of psychedelics that inspired it, that’s of a specific time. But there’s a throughline of human folly — of experimenting with forces b

eyond your control, that still resonates today. Altered States can better be understood in conversation with an equally bonkers time capsule — The Sixth Finger. An episode of the Twilight Zone-style show The Outer Limits, it tells the story of a man who turns into a weird, large-headed elf guy with six fingers by using a machine that accelerates evolution. It’s not the most, uh, scientifically rigorous work — the evolution process is literally controlled by a lever that switches between ‘forward

’ and ‘backward.’ Nor is it particularly frightening by today’s standards. But at the time, the concept of evolutionary horror was new. And it scared people. The episode was banned. Or at least, it almost was, before network executives stepped in and cut the ending where the lead devolves helplessly from a primate into primordial goop — their humanity erased. And sure, part of why this was cut was due to fear of anti-evolution backlash — this was the early 60s — but either way, this idea unsettl

ed people. For all their silliness, Altered States and The Sixth Finger are intriguing warnings against tampering with the laws of nature. In changing the source of the mutations from a hostile external force into something self-inflicted, they become parables of human ignorance — depicting evolution as an unstoppable power that will change you utterly if you mess with it. For what could be scarier than a destructive force beyond your control that you bring upon yourself? …I mean, getting chased

by a monster, probably. On a surface level, the Xenomorphs of the Alien franchise seem like the complete opposite of horror derived from the altered self. They’re the ultimate external threat, the other with a capital ‘O’ — something fundamentally inhuman and dissimilar from the protagonists they hunt. Especially with their decades of extra baggage from sequels, today, Xenomorphs feel more like nonspecific monsters than a reflection of ourselves. Yet the design of the alien didn’t start as an a

lien — it comes from a portrait of a biomechanical humanoid by Swiss artist H. R. Giger. Altered humans are central to Giger’s art, often appearing in tableaus where body parts seem to melt and merge with the mechanical. Yet even at their most extreme, Giger’s subjects somehow always register as humanoid. It’s this faint recognition that makes the Xenomorphs of Alien so frightening — this tug at the back of your mind that the thing chasing you is somehow familiar. As parasites that reproduce by

growing inside their hosts, the Xenomorphs are in some ways altered humans. It’s been established over the course of the franchise that the aliens take DNA from the lifeforms they develop within — able to steal the things that make us human, like our bipedal stature, in order to more effectively hunt us. But ultimately, the Xenomorphs are, of course, not actual people. The same cannot be said for the monsters in Dead Space. Recently remastered, Dead Space is a horror game that traps you within t

he Ishimura, a massive ship that is essentially a giant tomb haunted by the vengeful dead. Necromorphs are hostile lifeforms clearly inspired by the Xenomorphs, all the way down to their name, but the difference is that each Necromorph was once a living member of the crew — now mutated into unfeeling monsters. It’s a small change that profoundly alters the flavor of terror you experience, because now every enemy you slay comes with the palpable knowledge that you’re fighting something that was o

nce just like you. While playing, you find yourself wondering if each Necromorph’s human mind is still in there, watching their bodies do nightmarish things while being helpless to stop them. And if you fail, you know that you will suffer the same fate — doomed to live eternally as an inhuman shell. There’s enough isolated space station horror that it could be considered its own genre, but I think part of why many aren’t as effective is because they make the inevitable hostile lifeform too unfam

iliar. A huge part of what makes Alien and Dead Space frightening isn’t just that the characters are being hunted by a monster, but that they’re being hunted by a distorted echo of themselves. And I don’t think there’s any movie that captures this nightmare better than John Carpenter’s The Thing. While set in Antarctica instead of in space, The Thing no doubt belongs to the same isolation genre. In the film, a group of researchers are stalked by an organism that digests and replicates its victim

s. The lifeform in The Thing is constantly shapeshifting, its myriad of forms brought to life with visceral practical effects. But what’s even scarier than dripping, bodily terrors is how the film captures the agonizing paranoia of being hunted by a perfect imitator, that can look and sound almost exactly like you, but isn’t you… (The Thing screams). The most unsettling forms the thing takes are not when it appears like a horrific monstrosity, but when it’s indistinguishable from other humans. T

he film practically smothers you with its atmosphere of doubt and isolation, to the point where you feel like you’re trapped alongside the characters. In an earlier black-and-white film based on the same novel, the alien is… just a guy in a monster suit. Aside from being less scarry, this threat is surmountable — able to be overpowered by military men with nerves of steel, a sentiment reflective of the 1950s. It’s not our evolutionary superior or flawless imitation, because surely no alien could

rival us and our mighty intellect. Right? In an earlier version of the Alien script, the film would have concluded with the Xenomorph perfectly mimicking a crewmember’s voice to send out a distress signal, and then waiting to be rescued by another ill-fated crew. And so, what was once barely humanoid ends up near-flawless impressionist… Stories like Alien, Dead Space, and The Thing take the fear of the altered self and make it external, pitting humans against their own warped reflection. And th

e outcome of these films challenges our notions of human superiority — the very idea that we’d be difficult to imitate or outwit. It’s no accident that most of these movies end with few or no survivors. They remind us that in the game of evolution, humans can be outcompeted just as easily as any other species… Yet notably, not all works of evolutionary horror are nihilistic. And perhaps no film walks the line between dreams and nightmares quite as closely as Alex Garland’s Annihilation. Loosely

based on a novel of the same name, Annihilation is, ultimately, a movie about change. The story follows four scientists on their expedition into The Shimmer — a hallucinatory region where everything refracts and mutates into new forms. Which means that unlike most stories in this genre, it’s not just humans who are mutated. Within the haze of The Shimmer, plants meld together with their neighbors, animals take on the properties of other species, and even light waves seem to blend into glassy new

forms. And while some of these alterations are dangerous, others seem benign. Annihilation isn’t just disturbing — it’s also beautiful. Most stories in the altered self-genre focus purely on repulsive mutations. Scorn is a game that absolutely fits into this category. In that world, altered humanoids ooze out of every crack and crevice, their bodies twisted to be used as batteries, or computers, or a source of raw material. It’s a realm utterly stripped of humanity, where ugliness is pretty muc

h the only thing that remains. And side-note: despite the avalanche of unsettling imagery that they’re subjected to, the playable character quite literally has no mouth with which to scream. But Annihilation stuns just as often as it distresses — making it a story as much about creation as it is destruction. At times The Shimmer seems like a cancer — a disease eating away at the land meant to mirror the self-destructive tendencies of the main characters. At other points, it feels like nature rec

laiming itself, reveling in the inherent disorder of evolution. It’s unclear if The Shimmer has any malicious intent whatsoever. It may simply be evolution personified — an impartial engine of creation. “It was destroying everything.” “It wasn’t destroying. It was changing everything. It was making something new.” Not all the visuals of Annihilation are necessarily meant to be taken literally — it is a film, like The Shimmer itself, that is endlessly interpretable. But the film leaves you with t

he possibility that change — even radical, self-altering change, isn’t inherently negative. Indeed, not all works of evolutionary horror are quite as nihilistic as they appear at first. The famously grim All Tomorrows also has a surprising amount of optimism, as many of the mutated humanoids re-evolve their intelligence and form new societies — seemingly suggesting that even in an inhuman form, the human spirit can remain. Even I Have No Mouth, and I Must Scream has a faint glimmer of hope. At t

he end of the short story, the narrator finds a way to put the other four humans out of their misery. Although the narrator knows this is an act that will doom them to eternal solitude and torment, they perform it anyway — proving that there was still a spark of human compassion that AM wasn’t able to snuff out… Like any genre, not all evolutionary horror takes the same approach or reaches the same thematic conclusions. Nor is everything that falls within the category inherently effective and te

rrifying — in fact, some of it is pretty goofy. There’s a sci-fi film from 2001 about a meteorite that speeds up natural selection, simply titled Evolution, that takes a lot of the themes mentioned here and mainly plays them for laughs. While the film wasn’t received particularly well, it is interesting to see these tropes taken in such a radically different direction. Furthermore, what works of sci-fi actually belong to evolutionary horror can be tricky to define. The aliens in A Quiet Place lo

ok spooky, and we can assume they ‘evolved,’ but evolution itself isn’t really present or thematically relevant to the narrative in a meaningful way. Most stories featuring Zombies lurch along the line of the subgenre to varying degrees — with most involving some disease that alters the humans it contaminates. In many zombie movies, the terror comes from more from the scale of the hordes and the conventional thrill of being chased by something dangerous than from physical changes to the infected

. Some exceptions, like The Last of Us, exist — as in that franchise, more fear is extracted from the fundamental ways the fungal infection alters its hosts. Additionally, more emphasis is placed on how the cordyceps function biologically and how they evolved, earning it a clearer spot in the genre. Although since this is a category that I came up with while developing this video, I’d say it’s still debatable what stories belong in its ranks — and I’m sure there are a few I’ve overlooked. In the

end, perhaps it’s no surprise that Evolutionary Horror is such a scary hidden genre of sci-fi. If thought about in abstract terms, evolution is an almost eldritch concept — a law of the universe that changes all organic beings, from humans to the tiniest cell. Whether those changes are nonthreatening or nightmarish depends on the story and your point of view — but the one thing that stays consistent across the subgenre is that fighting evolution is futile — and playing with it is dangerous. Fro

m the slime we came, and to the slime we will return. As always, thanks for watching. If you enjoyed this entry, please lend your support by liking, subscribing, and hitting the notification icon to stay up to date on all things Curious. See you in the next video.