Alien

• Also known as Linguafoeda acheronsis,Xenomorph,Xenomorph XX121

Aliens (xenomorphs, to distinguish from other extraterrestrials, though they were not named this in the first film) are bipedal or quadrupedal depending on their host species. Aliens are skeletal and biomechanical in appearance and are usually colored in muted shades of black, gray, blue or bronze. Their body heat matches the ambient temperature of the environment in which they are found, so they do not radiate heat, making them indistinguishable from their surroundings through thermal imaging. Adult aliens can run and crawl along ceilings, walls, and other hard surfaces. They have great physical strength, capable of breaking through welded steel doors in numbers. Unlike many other extraterrestrial races, aliens don't have a technological civilization or make tools; they are primal, predatory, and absolutely adaptable. They have no fear and no mercy. They will destroy anything that attacks them. With their acidic blood, tongues with teeth, and tails that can kill, Xenomorphs are one of sci-fi's most fearful alien species. Adapted to comic books from movies beginning with the 1979 Ridley Scott film, Alien, starring Sigourney Weaver, Xenomorphs have been popularized and merchandised throughout media channels including video games, toys, books, art, and more.