A Facehugger is a parasitic lifeform that hatches from Xenomorph Eggs. They serve as the second stage of the Alien's life cycle, acting as intermediaries for the Alien with the sole purpose to implant other living beings with Alien embryos. Different facehugger variants vary in size and appearance.
Facehuggers are small creatures with an appearance that is somewhat comparable to Chelicerata arthropods, such as arachnids and horseshoe crabs. They are beige in color and each of them possess four pairs of appendages, resembling a pair of skeletal hands fused together, which allow them to crawl rapidly, and a long spine-like tail adapted for making great leaps. Facehuggers lack visible eyes and any facial features, except for a single orifice located on the creatures' underside, which acts as an ovipositor to insert the Alien embryo. Facehuggers are parasitoid in nature. Their only purpose is to make contact with living hosts and implant them with the embryos. Facehuggers will remain within the Egg in suspended animation until a living being, preferably larger in size disturbs it. True to its name, the Facehugger will grip its legs around the victim's head and wrap its tail around the neck. In addition to carrying potent acidic blood in its body, the Facehugger can excrete acid as well when latching onto a host wearing protective headgear to infiltrate its host's protection. This was the case when Kane was attacked by one inside the derelict.
Upon making contact, the Facehugger administers a cynose-based paralytic in order to render it unconscious and immobile. After a successful attachment, the Facehugger will insert the ovipositor down the host's throat while simultaneously implanting an embryo. The Facehugger would remain attached to the host for anywhere from less than a minute to 16 hours, keeping them alive by aiding in their breathing to prevent the host from being smothered. Once the implantation is completed, the Facehugger detaches itself from the host, crawling away until it finally dies. The victim then awakens with no awareness of the implantation, believing themselves to have been asleep, and appears to have a normal, healthy bodily function. The embryo implanted within the host will eventually develop into the next stage of the life cycle, the Chestburster.
Once a Facehugger has successfully attached itself onto a host, it is almost impossible to remove to prevent implantation. Attempts to remove Facehuggers generally prove fatal to the host, as the parasitoid will respond by tightening its tail around the host's neck, and its acidic blood prevents it from being cut away. In addition, its grip on the host's head is strong enough to tear the host's face off if it is forcibly removed. One instance of a Facehugger removal was documented on Hadley's Hope. The colony's medical staff attempted to remove a Facehugger from colonist, John Marachuk. Although they suffered one casualty, the remaining staff continued with the operation and successfully pulled it off of Marachuk's face. Unfortunately, Marachuk died shortly after the removal due to traumatic shock and poisoning that was caused by the Facehugger.
Dark Horse Comics
The following information follows the continuity from Dark Horse Comics' Aliens comics and all related media, therefore unrelated to the primary continuity.
The Facehuggers appeared in Dark Horse Comics' Aliens comic book series, set on an alternate continuity following the events of Aliens.
The Facehugger made its first appearance in the 1979 film Alien. The Facehugger and its proboscis were made from a sheep's intestine, while the effects of the creature leaping out of the Egg was achieved using high-pressure air hoses. The shot was reversed and slowed down in editing to prolong the effect and reveal more detail. For the scene in which the dead Facehugger is being dissected, director Ridley Scott used pieces of fish and shellfish to create its viscera.
The Facehugger was the first creature designed by H.R. Giger for the film, though the creature went through several versions in different sizes. Giger's original design for the Facehugger was a much larger creature with eyes and a spring-loaded tail. Later, in response to comments from the filmmakers, Giger reduced the creature's size substantially. At first, Giger assumed that the Facehugger would wrap around the outside of the astronaut's helmet, but Scott decided that it would have far more impact if the Facehugger were revealed once the helmet was removed. Scott and Giger realized that the Facehugger should burn through the helmet's faceplate with its acid blood; subsequent redesigns of the space helmet included a far larger faceplate to allow for this. Alien screenwriter Dan O'Bannon also conceived an initial design for the Facehugger, envisioning it as somewhat resembling an octopus, possessing tentacles. However, when O'Bannon received Giger's designs, which substituted tentacles with fingerlike digits, he found Giger's design concept to be superior. Since no one was available at the time, O'Bannon decided to design the Facehugger prop himself. The technical elements of the musculature and bone were added by Ron Cobb. Giger's initial design for the smaller Facehugger had the fingers facing forward, but O'Bannon's redesign shifted the legs to the side. When the foam rubber sculpture of the Facehugger was produced, O'Bannon asked that it should remain unpainted, believing the rubber, which resembled human skin, was more plausible.
The Facehuggers returned for the 1986 sequel Aliens. According to special effects supervisor Stan Winston, approximately 15 Facehugger props were made for the film. Each one depicted various states of the creature, including dead and decomposing ones, dissected ones, and living ones that do different things. For the sequence where Ripley and Newt are trapped in the MedLab, director James Cameron had the special effects crew construct a fully functional Facehugger puppet capable of movement. In addition to make the Facehugger appear as if it jumps off of a table, Cameron used backwards-filming, setting up the Facehugger on the table leg, then dragged it off and later edited the piece of film to play backward to make it appear to be moving forward towards Ripley. An additional Facehugger puppet was also built for the scene where the survivors encounter the live creature inside a preservative tank. This puppet used the same mechanism used for one of the "flying piranhas" featured in Cameron's directional debut, Piranha II: The Spawning. The puppet was cable-operated, requiring up to nine people to operate it: one person for each leg and one for the tail.
In Cameron's first draft of Aliens, Ripley was going into more detail about the Facehugger during the Colonial Marines' debriefing scene, calling it "a walking sex organ" to which Hudson replies, "Sounds like you, Hicks." It was cut from the final film.
In the special edition of Alien 3, a "Super Facehugger" is introduced. This would carry the embryo of the Queen Alien, but it was ultimately dropped from the theatrical version of the film. The Super Facehugger is found by Murphy in the Assembly Cut of Alien 3, but not identified as such.