Aliens

Aliens are extraterrestrial creatures from unknown planets.

Background
It is not known from what system and what planet they come from. Orbiting and observing the Earth with two motherships (Zeta and an unnamed one) at least since the 1600s in the Solar System, humans had no real awareness and no evidence of their existence. Before the 1960s, they were only believed by "crackpot" groups such as Quaere Verum, that believed in the existence of aliens and that they were being covered up by a government conspiracy.

But after the mysterious disappearance, or rather abduction, of the USSA space capsule Clarabella 7 and the pilot astronaut Colonel Hartigan during the 1960s Space Race, the existence of aliens became nationally recognized. It is said that alien technology was the basis of many of the Enclave's more exotic and impressive weaponry and robotics. Even toy manufacturers such as Wilson Automatoys weren't immune to these accusations and the United States government, which was said to keep its alien specimens and technology mostly in Area 51 (like a flying saucer that was after re-captured by aliens but crashed in California probably during the flight sometime after the Great War, instantly killing the two alien pilots).

The Brotherhood of Steel around 2161 and the Shi around 2241 encountered the bodies of aliens or their spaceships. By extension, the Capital Wasteland Brotherhood of Steel have a moderate amount of alien power cells kept in the Citadel's armory and the Brotherhood Outcasts also have some alien power cells at Fort Independence. Also before 2277, an alien body was discovered in Fort Bannister, probably by the Enclave, carrying what may have been recovered (like an alien blaster and some alien power cells) in the armory of the mobile base crawler at Adams Air Force Base.

Some of the advanced human technologies were created by using the alien technology like the AI project number 59234, created in the 2050s who manages the entire Sierra Army Depot Skynet and (allegedly) the device blocking telepathic and psychic commands, the psychic nullifier.

Bone aliens


These aliens appear only in the Fallout special encounter alien ship and are distinguished by their small skeletons in proportion to their overly large skulls. The Vault Dweller can come upon this unique occurrence in the wasteland of Southern California.

Zeta aliens


Zetan aliens are the only extraterrestrials that could be considered a faction. Aliens are relatively small, green yellowish-skinned humanoid beings with no primary sex characteristics. Their bodies are elongated with a small chest, are lean and lack any muscular definition. They also display no body hair of any kind. Their legs are shorter and jointed differently than a normal human and their limbs are also proportionally different than a normal humanoid; their humerus and femurs are the same lengths as their forearms and tibias.

Their heads are unusually large in proportion to their bodies and no noticeable outer ears or noses, instead only having small orifices for ears and nostrils. They have very wide mouths, no teeth, a light green tongue and large opaque black eyes with no discernible iris or pupil. Their hands have only three long suctioned-cupped fingers and no thumbs, however their fingers are so long they can wrap around objects and use any objects like any other humanoid species. They seem to breathe a similar atmosphere that humans do and process nutrients through the body with green blood. They subsist on a diet of unknown worm and squid food.

Zeta alien squid food


This extraterrestrial calamari is a type of food to the zetan aliens.

Zeta alien worm food


This extraterrestrial worm is a type of food to the zetan aliens.

Flatwoods monster
An alien encased in a purple space helmet, which obscures its face save for its glowing white eyes. The rest of the body is sealed in a protective suit, with an armored breathing apparatus and a large spade-shaped frill on its back. Flatwoods monsters have no visible legs, the suit instead terminating to a bullet-shaped point at its bottom, with what appear to be small hover-jets around the waist, allowing the creatures to float above the ground. The Flatwood monsters' long arms are tipped with large, three-fingered hands clad in large black gloves.

Encounters

 * In Fallout, the Vault Dweller can encounter a device based on alien technology and a flying saucer with two alien skeletons.
 * In Fallout 2, the Chosen One can encounter two technologies based on alien technology, bio med gel and Skynet.
 * In Fallout 3, the Lone Wanderer can encounter a downed recon craft named Theta and a dead alien, and can be abducted by a mothership named Zeta.
 * In Fallout 4, the Sole Survivor can witness the crash of a zetan UFO, creating a crash site, and encounter and kill the still-living hostile pilot in order to attain an Alien blaster pistol. Also during the Creation Club quest Over the Moon, the Sole Survivor encounters a zetan UFO as it drops off 2 zetans; one carries an alien atomizer while the other carries a disintegrator.
 * In Fallout 76, the Vault 76 residents can randomly encounter Flatwoods monsters and possibly zetans.


 * In Fallout: New Vegas, the Courier can encounter an unnamed recon craft with two aliens and an alien captain around.

Crashed ships
Five alien ships are known to have crashed in the United States:
 * A flying saucer in California (Fallout).
 * A recon craft named Theta in Capital Wasteland (Fallout 3).
 * Another recon craft that crashed and exploded on contact with the ground near the Lone Wanderer in the Capital Wasteland (Fallout 3).
 * At the Citadel, there is information on a terminal (in the A-Ring) about another ship of unknown type named Palandine that crashed in a heavily wooded area which the government was not able to reach.


 * A recon craft with three aliens near Horowitz farmstead in the Mojave Wasteland (Fallout: New Vegas).

Appearances
In Fallout and Fallout 2, they only appear in the form of skeletons. The crashed recon craft Theta appears in Fallout 3 with the first dead alien, and the aliens are the primary antagonists of the Fallout 3 add-on Mothership Zeta. They also make an appearance in Fallout: New Vegas if the player has the Wild Wasteland trait. If the player has the associated trait then they are spotted in the up most northern part of the map near Brooks Tumbleweed Ranch. In Fallout 4 you can find a crashed UFO, with a trail of green blood leading to the Alien and its Blaster.

Behind the scenes
The aliens resemble Grey aliens, beings commonly described in alien abduction accounts and commonly depicted in 1950's science fiction that have come to represent the "stereotypical" alien.