Alien

These creatures are the result of alien experiments on abducted humans. They are found on the board of Mothership Zeta. While there is some evidence of the existence of alien life forms, it is very scarce. Until the events of the Fallout 3 add-on, Mothership Zeta there was no record of direct contact between humanity and the creatures.

The Brotherhood of Steel and Shi have encountered the bodies of alien life forms or their spaceships, as did the pre-War United States government, which kept its alien specimens mostly in Area 51. By extension the Enclave and Brotherhood Outcasts also have access to alien technology; Alien Power Cells can be found at Fort Independence and in the armory of the Enclave's Mobile Base Crawler. They can also be found in the Citadel's armory (if you choose to destroy the Citadel during Who Dares Wins).

Crashed ships
Three alien ships are known to have crashed in the United States, with a possible fourth:
 * Alien Ship in California
 * At the Citadel, there is information on a terminal (In The Archives), about another ship that crashed in a heavily wooded area, and the goverment was not able to reach it.
 * Recon Craft Theta in Capital Wasteland (Fallout 3).
 * An alien ship can explode over the head of the Lone Wanderer in the Capital Wasteland during a special encounter although the cause of the catastrophe is unknown.

Alien technology

 * Alien Blaster - a weapon of alien origin. There are two versions that exist, one in Fallout 1 and Fallout 2 and another in Fallout 3 (Fallout, Fallout 2, Fallout 3)


 * Firelance - a unique variant of the Alien Blaster. (Fallout 3)


 * Alien Power Cell - the power source for the Alien Blaster. (Fallout 3)


 * According to its own (potentially unreliable) records, the Skynet computer was created based partly on alien technology. (Fallout 2)


 * Alien Epoxy - Alien repair technology.


 * The Fallout 3 add-on Mothership Zeta introduced several new alien weapons into Fallout 3;
 * Disintegrator
 * Alien Atomizer
 * Drone Cannon


 * Alien Robotics - introduced in the add-on Mothership Zeta, alien robots.

Appearances
Crashed alien ships appear in Fallout and Fallout 3. Alien Blaster appears in Fallout, Fallout 2 and Fallout 3. Aliens also appear and abduct the player in the Fallout 3 add-on, Mothership Zeta.