Aliens

Aliens are life-forms found on planets and moons alike. Currently known species include various types of arthropods, usually hostile when approached. Some genera are nocturnal and very aggressive, mostly capable of locating an astronauts position. Some types tend to prefer dark caves, which they use as breeding and feeding grounds.

Known species
Currently known life-forms living on Proteus 2 are very aggressive and pose a serious threat to small colonies early on, due to the lack of proper defense systems.

Hostile

 * Arachnoid: Vicious, gangly aliens.
 * Crab monster: As the name suggests, quadrupedal monstrosities capable of devastating charges. It is bigger than every alien other than the Giant worm
 * Skeliopod : A fast slithery creature.
 * Parasyte: Aggressive alien beetle
 * Jaculus: Large sectional snake
 * Gnat: Four legged, jumping, carnivorous creature. Mainly nocturnal.
 * Giant worm: A large subterranean creature that dwarfs other monsters and can launch itself in large, arcing jumps, crashing back to the ground and instantly digging into it, consuming whatever is unfortunate enough to be in its path.
 * Salamander : A fast aggressive creature (living on Aziel)
 * Snub : A 4 legged beetle like creature. Found on Proteus 2
 * Magma Demon: Massive aerial behemoth. Found on Zer
 * Cerberus: Towering, fiery beast, standing more than twice the height of an average human. Found on Zer
 * Hell Hound: Medium-sized, fiery dog-like creature. Found on Zer
 * Meduzoid:Small, floating, jellyfish-like creature. Found on Zer
 * Igneopod:Small, worm/leech creature. Found on Zer in the lava pools.

Neutral
These creatures will not attack if you do not attack them.


 * Tumbo: Large tortoise like creature
 * Colossus: Large, beetle-like alien. Discharges hurtful liquids as a purely defensive mechanism.
 * Orcek : Passive ostrich-like creature
 * Cow Giraffe: Peaceful animal, possibly herbivore (living on Aziel)

Unique

 * Ghost: Ethereal creature, found in certain locations (Mark Watney Base, Refinery Site: Alfheim) at night on Proteus 2. Can only be damaged by the Charge Rifle.
 * Queen Cleo: Hive Queen, found at the bottom of Mine: Magni on Proteus 2.

Level of difficulty
Encounters with aliens can vary in difficulty, primarily depending on the options selected in the customization screen. Moving the sliders will impact alien health (how much damage they can absorb before they die), alien attack damage (how much damage they deal to the player) and their overall numbers. Moving the alien slider to the left (none) will not spawn any creatures, except for the giant worm.