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When our present-day astronomers think about life on other planets, a term that gets thrown around a lot is the "Goldilocks Zone", the range of distances from the parent star where a planet could have liquid water. This is the only range of temperatures where life as we know it can exist; the only life-bearing planet we know of is in Sol's Goldilocks Zone, and all life on it requires water.

Some alien life in fiction, however, does not roll that way. These lifeforms live in glowing-hot worlds with molten metal in their veins, or on icy ones with liquid helium metabolisms. The planets they live on are generally Single Biome Planets by our standards, although they may be lush and varied to local eyes, and their inhabitants may seem like Elemental Embodiments. They're likely to be Starfish Aliens due to the radically different environment, though they can take more recognizable forms. More realistic versions of Silicon-Based Life tend to live in



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    Anime and Manga 
  • Neon Genesis Evangelion has The 8th angel Sandalphon, which looks like an Anomalocaris. It was discovered in a volcano in embryonic form, and later ages rapidly to a subadult form, it was shown to be completely unaffected by lava both internally and externally, and was able to swim it in as if it was water.

    Comic Books 
  • Planet Hulk: The spikes are a race resembling the symbiotes, who naturally float in the vacuum of space and feed off cosmic radiation. They're usually peaceful, but become starved and aggressive in terrestrial atmospheres and become parasite zombies.

    Films — Live Action 
  • Star Wars: The Kel Dor species that Jedi Plo Koon belongs live on a planet poor in oxygen and rich in Dorin Gas and helium, the former they breathe like most aliens breathe oxygen. They have to wear special masks in terrestrial environments due to finding oxygen toxic.

  • The Venber in Animorphs melt in above-zero temperatures. They nearly went extinct when it turned out the resulting liquid had many useful properties.
  • In Isaac Asimov's short story Buy Jupiter, a race of aliens is described which lives inside O-class stars. The Sun is too cold for them.
  • Poul Anderson's 1957 novellete "Call Me Joe" features a paraplegic who explores the frigid surface of Jupiter via a remote-controlled, centaur-like artificial body that's designed to drink methane and craft tools out of water ice. He encounters hostile wildlife which evolved there, hence is also adapted to such conditions.
  • In The Chronicles of Narnia, there's a deep subterranean land called Bism, which is very hot and features such wonders as fire salamanders and fresh gems full of delicious juice.
  • In Terry Pratchett's The Dark Side of the Sun, there are the Creapi whose homeworld saw them evolve in molten phosphorous sulphides. When they spread into space, they simply redesigned themselves to fit the changing situations they encountered. Half a million years of forced evolution has created the middle-degree Creaps, who are happy at a mere 500 degrees C. The divergent High-Degree Creapii live on the outer surfaces of relatively cool stars. Wherever a star pushes the ambient temperature to beyond the melting point of tin, there you will find Creapii. In fact, they bartered with the human race, who were happy to sign over squatters' rights to the planet Mercury in exchange for Creap technology. To interact with humans they wear "spacesuits" that preserve life at habitable temperatures in what to them is a freezingly sub-zero hostile environment.
  • ''Discworld
    • Trolls are living rocks whose brains are impure silicon, meaning they're slow and stupid under the snowline (and extremely intelligent in the cold). However, they are still susceptible to freezing to death.
    • Golems are made of clay, so they're resistant to a lot of things like lightning (allowing them to be atheists when Discworld gods are trigger-happy with the Bolt of Divine Retribution), heat (they can walk through fire and hold liquid metal), cold, and extreme pressure (one was buried on the ocean floor for centuries). As we find out in Going Postal, they can't take extreme heat and cold at the same time.
  • Robert L. Forward's Dragon's Egg. The Cheela live on a neutron star. The gravitational pull on its surface 67 billion times that of Earth.
  • In Iceworld, Ken's species come from a planet even hotter than Mercury, where the air is gaseous sulfur and the oceans are molten zinc, and they have to make a crater into a giant parabolic mirror in order to keep their base warm on Mercury. Their researchers are amazed to discover life on a newly-discovered system's third planet, which is so cold the liquid medium is hydrogen oxide.
  • Kir Bulychev
    • Alice, Girl from the Future: An airless chasm on an asteroid converted into a Generation Ship is inhabited by "ice dragons" - octopus like creature possibly inspired by the Lucky Starr example. There are also sapient species fitting it - for example, a hotel on one planet was described as too hot to touch despite a thousand layers of insulation.
    • Bulychev also has a short story about a man who fell in love with a female alien - she looks like a human female, and a beautiful one, but her biochemistry is based on ammonia rather than water.
  • Outsiders from Known Space are vacuum breathers with a metabolism based on liquid helium, and the series also occasionally features amoeboids with superfluid helium liquid media.
  • The Laundry Series speaks of the Chthonians, codenamed DEEP SEVEN, who live in the upper regions of Earth's mantle.
  • In the Lucky Starr series, creatures are discovered on Mercury - looking like rock made octopi draining heat from any source they find, like lone miners.
  • Played with by Douglas Adams in Mostly Harmless. He notes that life can exist in all sorts of hostile environments, such as the intoxicating seas of Santraginus V, the fire storms of Frastra, and even New York.
  • Hal Clement's short story Proof is about creatures who live in star cores and have difficulty believing in conditions under which regular elements become solid.
  • The Sector General universe has one culture who are sentient crystals of frozen methane and can only survive close to absolute zero, another culture who are only comfortable at molten-rock temperature (the previous two require very heavily-insulated encounter suits to interact with other sentient species), and a culture of Hive Minded radiation-eaters who live inside the space station's main reactor pile.
  • The short story Spacehounds of IPC features inhabitants of Titan, who as the moon cooled and they evolved had to terraform the place with a fluorine atmosphere just to have something reactive enough to metabolize with in the cold, and have kiln-suited foundry workers making stuff out of water. They're very glad when they first encounter humans, since their power station on Saturn was out of order, and the environment there would be only annoyingly warm for a human but a deadly inferno for them.
  • This is actually the norm in the Star Carrier series. The Sh'daar Masters state in the third book that out of around 50 million sapient species they've encountered, humans are only the twenty-thousandth or so with a carbon/nitrogen/oxygen/water metabolism. The first book alone shows species both intelligent and not that evolved on planets more like Venus than Earth, and the third mentions intelligent but non-technological life forms in the depths of Europa's ocean.
  • In The Star Diaries, Ijon Tichy is viewing a video filmed by a probe on a half melted planet. A local professor complains about the cold of 860 Celsius, and dismisses the idea of creatures living on planets as cold as Earth. Another part has a catholic priest complaining about the difficulties of preaching on a certain planet - its inhabitants are freezing at 600 Celsius, so of course they are more interested in Hell than Heaven
  • Sundiver features creature that live in the photosphere of the sun, and and are defined more by magnetic fields than chemicals. Some of them are even intelligent, although the "communications" from them during the story events are a hoax.

    Live-Action TV 
  • Doctor Who
    • Whatever it was that haunted the planet in "Midnight". It was capable on surviving a planet bathed in the X-tonic radiation of its sun, a place where no known life is capable of existing.
    • The Pting from the episode "The Tsuranga Conundrum" lives in space, is essentially impossible to destroy, and foregoes conventional food, subsisting instead on energy drained from technology.

    Multiple Media 
  • Star Trek has several examples
    • The Tholians from Star Trek: The Original Series are high temperature extremophile bug-like aliens. Being subjected to anything lower than 380 degrees Kelvin could crack their carapace and kill them.
    • Star Trek: The Next Generation has at least two:
      • The huge jellyfish-like aliens seen in "Encounter At Farpoint", luminous and pliant, yet able to survive nicely in the vacuum of space.
      • The "Brancher" alien, also known as the Crystalline Entity, is an enormous tree-like crystal that absorbs the life energy of entire worlds. It is first encountered in the episode "Datalore", where everyone on Omicron Theta had been consumed by the entity, leaving only the deactivated android Lore intact. This brancher likewise can travel easily through the vacuum of space.
    • Star Trek: Voyager has the Silver Blood, a deuterium-based race encountered on a Class Y planet in the episode "Demon". The episode takes its name from the fact that Class Y planets are sometimes termed "demon" worlds because they're basically Fire and Brimstone Hell (start with temperatures averaging 500 Kelvin and go downhill from there).
    • Star Trek Online:
      • In addition to the Tholians, the game has the unseen Nukarians from Nukara Prime, another Class Y planet. The Nukarians, and the Tholians who are trying to take over the planet, can walk around on the surface unprotected but humanoids catch fire instantly if they go out of the Nukara Task Force's environment shield without an EV suit.
      • The Foundry mission "Relics" has the extinct Ugcinians, yet another species from a Class Y planet. They went extinct hundreds of years ago because their sun went supernova and their starship technology wasn't up to duplicating a Class Y atmosphere.

    Mythology And Religion 
  • In the realm of mythology and folklore, medieval and earlier thinkers such as the alchemists believed there were fire-lizards, salamanders, that thrived in extremely hot environments such as the inside of volcanoes and deep underground and could withstand heat and pressure that would kill most other life-forms.

    Tabletop Games 
  • Eclipse Phase features many Transhuman morphs adapted to extreme environments. Ranging from the "mundane" Rusters adapted to the half-terraformed environment of Mars to Hulders that barely qualify as "biomorphs" and wander the surface of Titan herding similarly modified caribou, and Suryas, Space Whales that live in the corona of the Sun.

    Video Games 
  • The Lanius from FTL: Faster Than Light are metallic beings who have no trouble living in vacuum. They don't have trouble living in pressurized environment either; they just suck out any surrounding air.
  • Lekgolo in Halo are an eel-like species that thrive in the ring system of a gas giant by consuming metals, can survive in a vacuum and the Flood find them difficult to infect because they can only infect one worm at a time, a trait that the Forerunners tried to exploit in their fight against the Flood. Thanolekgolo, a type of Lekgolo gestalt group, take this even further by surviving the thermonuclear detonation of a star ship's fusion engines that destroyed a Halo ring, being able to consume just about anything and end up being the only living thing on a fragment of of the ring.
  • Kirby: Triple Deluxe: Pyribbit, the boss of Endless Explosions is described as living near the volcanoes and thriving off lava and hot rocks.
  • The volus of the Mass Effect-verse originated on a planet with an ammonia atmosphere, with atmospheric pressure so much higher than most other races' homeworlds that they'll burst unless they wear heavy metal pressure suits.
  • Star Control:
    • In order to procreate and spread their colonies, the Mycon terraform Earthlike planets into lava hell holes.
    • The Slylandro are a race of intelligent gasbags who live on a gas giant.

    Web Original 
  • Orion's Arm has many human tweaks designed for extreme environments, such as unterraformed Venus or even outer space. And the actual aliens are usually adapted to environments very different from Old Terra. The first alien race encountered by Terragen life and one of the most psychologically similar, the To'ul'hs, originated on a planet that can be compared to either a cool and wet "Cytherean" world, or a very hot and high-pressure Gaian world (somewhere between Venus and Earth), though they've developed their own tweaks, some of whom are adapted to Gaian environments.

    Western Animation 
  • Ben Ten:
    • In the original Ben 10, Heatblast's species lives on the surface of a sun.
    • Ben 10: Alien Force features a planet that is sun-blasted on one side and ludicrously cold on the other, leaving a small barely-habitable band in the center. Ben asks who would want to live there; the answer is the Necrofridgians, or the mothlike Big Chill species.
    • Ben 10: Omniverse features tungsten-based lifeforms called the Kraaho who need life to be extremely hot to live. Since they decide to make a settlement on Earth, which is far too cold for them, they attempt to cause a lava flow on the surface to make it more habitable.
  • Futurama: "Mobius Dick" has the titular Space Whale. It lives in the fourth dimension, and breaches into the universe in order to fill its lungs with vacuum.

    Real Life 
  • Of course real life features extremophiles, although almost none of it is multicellular. There are microbes that live in volcanoes, ocean rifts, under the Antarctic ice... many examples. Giant tube worms are one of the few multicelluar examples of extremophile lifeforms, living deep under the Pacific Ocean around black smokers and tolerating extremely high hydrogen sulfide examples.

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