Xenomorph

Xenomorphs are roughly humanoid with a skeletal, biomechanical, or insectoid appearance. They possess an exoskeleton, and a whiplike tail that, in later incarnations, possesses a bladed tip. As Xenomorphs grow into adulthood, they generally have less and less of an exoskeletal structure as most or all of their skin is shed within the first day after leaving their host.

Some evidence contradicts the xenomorph exoskeleton. The DVD box set collection, the Alien Quadrilogy, shows a skeletal structure in x-ray images of a stage in its life cycle in each animated menu selection. Also, as noticed in Alien Vs. Predator and Predator 2, it shows what appears to be a xenomorph skull. No canon explanation exists to establish which of the skeletal structures are definitive.

Typical adults are about 7 feet 10 inches tall. They have a hard outer shell which is usually muted shades of black, bronze, or blue. They have an elongated, cylindrical head but lack visible eyes. Xenomorphs have been depicted as having variously four or six-fingered hands. The first and second fingers are joined together as well as the third and fourth, and if present, also have a second thumb on the lower edge of the hand.

Xenomorphs possess strong, sharp claws and their mouths contain double mandibles; that is, it has one mouth inside another mouth, akin to the pharyngeal jaws of the moray eel.^[2] The first mandible, which is similar to a human's, lowers and the second mandible is located at the tip of a proboscis that extends outwards from inside the first. More understandibly, the second mouth is located at the end of the alien's tongue. The aliens tongue can become rigid enough to penetrate bone or body armor with the secondary jaws at its tip. It is employed almost exclusively as a weapon to incapacitate prey, usually through head trauma. It can be seen when the Xenomorph opens its mouth slowly. The Xenomorph can kill its victim by using its claws or its tongue, which could rapidly bite and kill its victim easily; sometimes it can use its tail to stab the prey, as seen in the 2004 movie Alien vs. Predator and also in the 1986 movie Aliens, when the alien queen used its tail to impale the android, Bishop.

Xenomorph blood is an extremely potent acid, similar to sulfuric acid, and is capable of dissolving on contact almost any substance with alarming speed. The acidic blood is highly pressurized within their bodies, and any piercing or puncturing wound causes it to violently spray out in all directions. During the movie Aliens, a large number of people were either killed or seriously injured by this blood after shooting the aliens. As depicted in the films Alien: Resurrection and Alien vs Predator, the exoskeletons of the creatures themselves are impervious to their acidic blood. In the Alien novelization by Alan Dean Foster and Dan O'Bannon, the acid is not blood but a fluid maintained under pressure between a double layer of skin.^[3]

The adult xenomorph is essentially a living weapon, noted for its ferocity and deadliness in any condition. Once fully matured, they have great physical strength and agility. Despite their ferocity and savagery, like any skilled predator, they are masters of stealth. A favored method of acquiring prey is to simply wait in a dormant state until an appropriate victim strays near and then drop down silently from behind. The prey is generally blind to the fact that a Xenomorph is present, due to its propensity to camouflage itself within its nest walls or the surrounding artificial environment given its biomechanical appearance.

Adult xenomorphs are quick and agile, and can run along ceilings and walls, a skill they exhibit freely whether they are evading others, attacking, or hunting prey. They can survive in extreme temperatures, are well-adapted to swimming, and can survive in vacuum for unknown lengths of time. Their movement tends to be silent, and they do not radiate heat as their exoskeletal temperature matches the ambient temperature. They also salivate profusely.

The creatures possess no visible eyes; Giger mandated this in his original design, because he felt that it made the creatures much more frightening if one could not tell they were looking at them.^[4] In the original Alien film, the top of the creature's head was semi-transparent, with empty eye sockets of human appearance visible within. This element was dropped in later movies. In Aliens, the adult creatures are lacking the smooth carapace covering their heads. In Alien³, a fisheye lens (which creates a perspective similar to that of a peephole) was used to depict the xenomorph's sight. Whether this can be considered sight or just a filmed representation of the creatures' sensory perception is unknown. However, in the novelization of the movie Alien, the creature is held mesmerized by a spinning green light for several minutes. Due to the absence of clearly visible eyes, it is possible that the creature uses echolocation to see its environment, much like bats. It may be for this reason that xenomorphs hiss almost constantly, and as depicted in the Aliens vs. Predator games, the aliens can detect their prey using pheromones, much like a colorful aura around the body.

The creatures also have the ability to spit acid, though this seems to be a rare act, seen only in Alien³ and Alien: Resurrection as well as various comic books and video games.

Xenomorphs can also produce a thick, strong resin, previously used to build their hives and cocoon victims. Much like termites, they mix their viscous saliva with solids, like dead victims or dead/cannibalized xenomorphs. It shows amazing heat and moisture-retaining qualities, as seen in the hot, moist atmosphere of the hive in Aliens.

Xenomorphs appear to possess an intelligence roughly similar to that of a typical predatory mammal. Although they do not demonstrate human-level intelligence as a species (either through writing, tool use, or the development of any sort of technology), their queen appears to possess considerable acumen in its social behavior and manipulation of human technology, including, in Aliens, cutting the power to the colony and operating an elevator. In the director's commentary for Aliens, James Cameron noted that the xenomorphs in Aliens had been alive for far longer than the alien in the original, and so had more time to learn how to manipulate machinery, if only at the most basic level.^[5] Xenomorphs have demonstrated little actual emotion, though they are not totally devoid of fear, especially for their eggs. They seem to produce basic vocal sounds of hisses, clicks and high pitched shrieks.

In the Aliens literature, it has been suggested that the creatures have a hive-mind, or a collective consciousness directed by the queen. In the Aliens comic book series, as well some novelizations (produced before the Alien³ film), it is suggested that the Queen alien communicates telepathically with its potential hosts, through terrifying dreams and religious visions, leading to the formation of cults with the xenomorph as a god-like figure. Through cloning in the events surrounding Alien: Resurrection (noted in the novelization), it appears that the alien's hive mind includes a collective memory that passes along even at a genetic level, and through the tests conducted on Ellen Ripley, it is revealed that the memory passed from Ripley onto the new generation of Xenomorphs allows them to read and understand different languages. Xenomorphs are considered 'fast-learning', understanding cause and effect very quickly, demonstrated in Alien: Resurrection, as a scientist 'punishes' a group of Xenomorphs by exposing them to jets of liquid nitrogen when the creature attempts to break through the barrier dividing them. When the creature moves to do so again the scientist places his hand over the activation device, and the xenomorph quickly halts. The xenomorphs escaped by killing one of the three in their pen allowing the acidic blood to burn a hole in the floor. And later killed a guard who went in to investigate by using the same activation device the scientist had used on them.

In the rare event that a xenomorph should find itself under attack or otherwise vulnerable, it once again displays incredible creativity and cleverness. They are quite capable of moving quickly in ventilation systems, despite their size, and will use such conduits for ambush, escape, or simply as an easy way to travel between areas. Also, as demonstrated in Alien vs. Predator, a xenomorph can use the acidic blood from its own wound as a weapon. In that film, the tip of a xenomorph's tail was severed, and the xenomorph thrashed its tail about, in order to spray its acidic blood as a chemical weapon. (This method was also used to free the Queen in AvP: numerous xenomorphs punctured her skin, allowing her acidic blood to melt the chains holding her.) Should a xenomorph become separated from its hive, it will often try to re-establish contact as soon as possible.

Xenomorphs, in all stages of their life cycles, have been said to have vulnerabilities to heat, although this was never proven. In the first Alien, it is only assumed, but never actually demonstrated.

Cold temperatures are an inadequate precautionary measure -- except at the extremes, such as liquid nitrogen. In the first Aliens vs. Predator film, a Queen is shown to be quite active in the Antarctic environment. Since they can survive in vacuum and endure cold climates, it is unlikely they would be driven off by chilly conditions, but blasts of hot steam or cold air can be effective, especially when paired together, as shown in Alien: Resurrection. Applying both hot and cold temperatures in rapid succession apparently achieves a thermal shock effect on an xenomorph's exoskeleton, as shown when the exoskeleton of the xenomorph from Alien³ exploded after both falling into a vat of liquid lead and being sprayed with water, similar to rapidly heating and cooling glass.

Xenomorphs are shown to be vulnerable to high calibre and close-range small-arms fire as well as explosives, as demonstrated in Aliens. The film "AvP:R" shows the aliens vulnerable to small arms fire, ranging from 9mm to 5.56mm.

Xenomorphs are depicted as eusocial lifeforms with a defined caste system which is ruled by a queen. They reproduce as parasitoids and grow to full size very rapidly. The alien queen lays eggs that eventually release a single parasitic facehugger which can lie dormant for an indeterminant period of time (such as the unknown period between the time the Aliens impregnated an unknown extraterrestrial species and when humans discovered the Xenomorphs in the first Alien movie), until such time as a host is detected nearby. Facehuggers attack a host and slide a tubular proboscis down the victim's throat, implanting an embryo within their chest, which later develops into what is called a "chestburster". After implantation, facehuggers die and the embryo's host wakes up afterwards showing no considerable outward negative symptoms. Symptoms build acutely after detachment of the facehugger, the most common being sore throat, slight nausea, increased congestion and moderate to extreme hunger. In later stages where the incubation period is extended in preparation of a queen birth, symptoms will include a shortness of breath, exhaustion, and hemorrhaging (detectable through biological scanners and present in nosebleeds or other seemingly random bleeding incidents), as well as chest pains inflicted either in lack of chest space due to the chestburster's presence, or even premature attempts to escape the host.

The incubating embryo may take on some of the host's DNA or traits, such as bipedalism, quadrupedalism - as shown in Alien³ when the alien was born from a dog (an ox in the extended version) instead of a human - or also having mandibles (shown in Alien Vs. Predator with the 'predalien') and other body structure changes, possibly indicating the need to adapt using indigenous wildlife as a reference for what features to retain for use in that particular environment. Over the course of 1-24 hours (undeterminable in some cases, and sometimes up to a week, in the case of some queens), the embryo develops into a chestburster, at which point it emerges, violently ripping open the chest of the host. Without medical assistance or surgical removal, the victim will certainly die as a result of the emergence. Shortly after emergence, the creature grows rapidly to adult size and will feed on either the host or other prey to aid in its resource intake. It should also be noted that a new method of impregnation was introduced in "AVP:R" where the young Predalien Queen had the ability to impregnate a host orally without laying eggs. The directors stated that this is a new feature in the mythos that they have invented in which a young Queen does not lay eggs, but directly implants embryos into hosts so it can quickly establish a new hive. Once a hive is established, a mature Queen will develop a ovipositor and lay eggs. It is heavily implied that the Queen's eggs can then be carried around different locations by drones along with a cocooned potential host, as seen in Aliens.

Queen xenomorphs are significantly larger than the warriors or drones, approximately 4.5 m (15 ft) tall.^[6] Their body structure differs also, having twin sets of arms and being built more similarly to a theropod dinosaur than a humanoid. Queens have a much larger braincase than the average adults, protected by a large crest above their heads. Another well-known feature of the xenomorph queen is an immense ovipositor in its lower torso, which is responsible for creating facehugger eggs (similar to a queen termite). The queen is able to detach from the ovipositor. When attached to her ovipositor, the queen is supported by a "biomechanical throne"^[7] that consists of a lattice of struts resembling massive insect legs.

Unlike insect queens, there appears to be no need for drones to fertilize a xenomorph queen's eggs. In various comics and games, the drones are simply a "worker" caste. Alien: Resurrection indicates that the queens are born fertile.

The various novelizations and media produced on the creature in the years since its introduction also indicate that in the absence of a Queen proper, the Aliens can make an ordinary egg hatch into a new Queen, through the introduction of the xenomorph equivalent of Royal Jelly.

The design of the queen was created by Aliens director James Cameron in collaboration with special effects artist Stan Winston, based upon an initial painting Cameron had done at the start of the project. The Winston Studio created a test foam core queen before constructing the full hydraulic puppet which was used for most of the scenes involving the large alien. Two people were inside working the twin sets of arms and puppeteers off-screen worked her jaws and head. Although at the end of the film the queen was presented full-body fighting the power-loader, the audience never sees the legs of the queen, save those of the small-scale puppet that appears only briefly. In Aliens, Cameron used very selective camera-angles on the queen, using the 'less is more' style of photography. Subsequently the movie won an Oscar for Visual Effects.

It was only during the climax of the 2004 film Alien vs. Predator that for the first time audiences could see the queen actually running and fighting because of the computer-generated imagery techniques employed to create it. The queen's basic design was also altered to make her more "streamlined" in appearance and her over-all size was increased to 6 meters (20 ft) tall. Other changes include the removal of the "high-heel" protrusions on her legs, altering the joints so she could run faster, and making her waist thinner because there was no need for puppeteers inside her chest. The new Queen was built from scratch. The legs were made proportionally larger to the body, giving the new queen a sturdier appearance. These changes could have resulted from the fact that the queen from AVP is much older than any other previously seen, although its age is never specified.

The eggs are large, ellipsoidal leathery objects about one meter high with four-lobed openings at the top. Eggs are laid by a queen. They require a hot, humid environment in which to incubate. Once laid, the egg remains immobile until it senses a suitable host organism to support an alien embryo, at which point the egg opens and the facehugger erupts from it, launching itself towards the intended target. According to the pen and paper role-playing game, Aliens Adventure Game, any adult xenomorph may lay eggs. However, eggs laid by drones and warriors last only a few months. The eggs laid by the queens will protect the facehugger within for several centuries.

A facehugger is the second stage in the life-cycle of a xenomorph. Its bony finger-like legs allow it to crawl rapidly and its long tail can launch it in great leaps. These particular appendages give them an appearance somewhat comparable to Chelicerata arthropods such as arachnids and horseshoe crabs.

The facehugger is a parasitoid; its only purpose is to make contact with the host's mouth for the implantation process, by gripping its long, bony finger-like legs around the victim's head and wrapping its tail around the host's neck, then slowly tightening the tail in order to make the host gasp for oxygen and be rendered unconscious. By this point, the facehugger will have inserted a tube-like proboscis into the mouth and down the throat of the host, supplying the host with oxygen and implanting an embryo. Attempts to remove facehuggers generally prove fatal—the parasite will squeeze the host's neck with its tail. The facehugger's acid blood deters cutting it off. And its grip is so firm, peeling it off would result in tearing off the host's face. In Aliens, a number of facehuggers are observed in stasis and accompanying medical notes indicate that the human hosts died during removal. Over time, a facehugger's outer epidermis becomes solidified and hardened by a chitinous layer of silicon. Once the alien embryo is safely implanted, the facehugger detaches and dies. Later, a larval Xenomorph (Chestburster) will erupt from the host's chest.

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.^[8] Dan O'Bannon initially conceived the facehugger as somewhat resembling an octopus, possessing tentacles. However, when he received HR Giger's designs, which substituted tentacles with fingerlike digits, he thought Giger's design concept 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 them to the side.^[8] 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.^[9].

The chestburster is the immature adult form of the xenomorph which emerges forcibly from the chest of its host, killing it. The chestburster is similar in form to the fully grown alien but far smaller and pale in color.

The chestburster was designed by Alien special effects master Roger Dicken. Giger had produced a model of a chestburster that resembled a "turkey," and was far too large to fit inside a ribcage. Much to Giger's chagrin, his model reduced the production team to fits of laughter on sight.^[10] Scott drafted a series of alternate designs for the chestburster based on the philosophy of working "back [from the adult] to the child" and ultimately produced "something phallic," so Dicken was given the task to design it.^[10] The chestburster in Alien was armless, but arms were added to the chestburster in Aliens because Cameron believed that the chestburster in the first film was "too larval" for an upcoming adult Xenomorph.^{[citation needed]} The chestburster in Alien 3 was far more developed, possessing complete limbs.

Little is known about the transformation that occurs between the chestburster and adult phases. Although in Aliens vs Predator: Requiem and Alien3, we are led to believe that the xenomorph appears to have moulted. Maturity is reached in a matter of a few hours, and involves a dozenfold increase in mass, which would presumably require some form of nourishment. In the novelization of the movie Alien, Ripley comes across a food locker that had been raided, apparently by the alien to get food. Whether or not this was nourishment to grow was not specified. In the videogame, Aliens vs Predator: Extinction, the chestburster goes through a cocoon stage shortly after emerging from its host. A fully-developed xenomorph emerges from the cocoon afterwards.

In Alien: Director's Cut, the xenomorph has a second method of reproduction, whereby it could transform humans into eggs, as shown when Ripley discovers Brett and Dallas, cocooned in a viscous liquid. This method of reproduction allowed an alien a complete individual life-cycle, without the need for a queen.^[11] The alien was described in the bonus DVD as being "ambi-sextrous". However, since this scene was cut in the final released version of the film, allowing the queen to appear in Aliens, its canonicity is uncertain.

In another omitted scene from the script for Alien³, these eggs were actually cocoons, inside of which a human was painfully transformed into a full-grown alien, which then emerges from the cocoon like a perversion of a butterfly. This non-canon tertiary version of reproduction bypasses queens and facehuggers entirely. However, this scene was never filmed.

In Alien³, another addition was made. That of a 'super facehugger' that could impregnate two hosts with a Queen and a warrior embryo. This facehugger was large and black, very different to the normal pink variety. This would explain why both Ripley and a dog were impregnated from one facehugger. The super facehugger was found by some of the inmates, who thought it was a type of jellyfish.

In Alien vs Predator: Requiem the Predalien has the ability to impregnate a host directly without eggs that form into chestbusters. The directors stated that this is a new feature in the mythos that they have invented in which a young Queen does not lay eggs, but directly implants multiple embryos into hosts so it can quickly establish a new hive. Once a hive is established, a mature Queen will develop a ovipositor and lay eggs.

The xenomorph has been portrayed in noticeably different ways throughout the film series. Much of this was due to the continuing advancements made in the field of special effects, technology and techniques used to bring it to life. It has also been suggested, both on screen and in the games based on the Alien series, that the alien's form is affected by its host, so that different species of host will create different varieties of xenomorph. Variations within a host can also explain possible variations apparent in the xenomorph spawned. An example of this is seen in Alien³, when a dog (an ox in the extended edition) spawns a xenomorph with a distinct canine body structure and quadrupedal movement. It is also posible that there are different breeds of Alien that are not directly related, causing a difference in appearance. Furthemore, issues of the Aliens (comic book) and various versions of the Alien vs. Predator (video game) depict a "caste" sytem similar to ants and bees among the xenomorph hives (queen, warrior, drone, etc.), each with a different appearance.

In the original Alien film, and in the sequel Aliens, they are depicted as tall, slender creatures with a roughly human biomechanical design. Notably, the being in the first film is far taller than those in the second and third. In the later films, such as Alien: Resurrection and Alien vs. Predator, they are depicted as being shorter and bulkier organisms, as well as being more quadrupedal, portrayed by either the traditional 'man in a suit' technique for close-ups or full form using computer-generated imagery.

Originally, the xenomorph's tail was roughly the length of the rest of its body with a small, almost surgical stinger-like barb on the end. But from Alien³ onwards, the tail has extended in length and currently features a large, knife-like blade at the tip. In Alien: Resurrection and Alien vs. Predator, the tails have also supported a ridge of spikes right before the blade. This was introduced in Alien: Resurrection to help them swim convincingly, and was left intact in Alien vs. Predator. The tail itself is shown to be of incredible length during Alien vs Predator, measuring almost its full body length, as depicted when the Grid Alien impales a Predator from a ledge.

The original shooting script for Aliens featured a scene in which Lieutenant Gorman was "stung" by a xenomorph's stinger. He was not killed, merely stunned, and the barb remained lodged in his shoulder, having torn loose from the xenomorph's tail, much like a bee stinger. The novelization also included this scene, though the movie itself does not.^[12] This attribute is used later on in various games.

In Aliens, xenomorphs are depicted as having ridges along their cranium, while in all other films they have smooth cowls covering their skulls. It was speculated in the Aliens bonus DVD that this was due to these xenomorphs having had more time to mature, compared to the aliens in the other films. In the comics and various video games (Aliens versus Predator: Extinction, Alien vs Predator (SNES), Aliens versus Predator 2) this was depicted as one of the visual differences between the xenomorph drone and warrior castes. The drones (in this instance used to indicate a "worker" caste instead of mating-capable males) have the smooth cowl while the warriors display the ridges.

In Alien and Alien³, the xenomorph has six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides. In Aliens, the xenomorphs are shown with five fingers, with the second thumb missing. In Alien: Resurrection and Alien vs. Predator, the aliens have four fingers. No explanation is given in the films for the fluctuating number of digits.

In Alien and Aliens, the xenomorphs were plantigrade, meaning they walked with their feet flat on the ground (probably due to special effects limitations). In Alien³, the xenomorph is a runner type, owing to its quadrupedal host organism (see below). In accordance with the DNA assimilation theory, it is from its canine host that the xenomorph runner acquired digitigrade hind legs (meaning that it walked on its toes rather than the soles of its feet) and quadrupedalism. Interestingly, the Alien³ special edition had the xenomorph emerging from an ox rather than a dog, in which case the DNA assimilation theory suggests that the runner's hind legs would have been unguligrade rather than digitigrade. Since these two hind leg types are relatively similar (ungulates walk on the tips of their extended toes), it is safe to assume that this change would have had minimal effect on the xenomorph's overall appearance. Alien: Resurrection saw a dramatic redesign from previously-encounted humanoid breeds: the xenomorphs that emerged from human hosts in this film walked on digitigrade hind legs in a manner that does not conform with the DNA assimilation theory (humans are plantigrade organisms). This is complicated by the fact that the xenomorphs of the film were spawned by a queen grown from cells derived from a clone of Ripley, making their genetic heritage muddled at best. Also, the xenomorphs in Alien: Resurrection were often entirely digital, so it is possible that the film makers used the versatility of the medim to make them seem more menacing and predatory. ^[who?] In Alien vs. Predator, the xenomorphs return to their roots as plantigrade organisms, though their legs are sleeker and more skeletal in appearance, due to the use of computer visuals and hydraulic puppetry, rather than costumes.

The 'Runner', otherwise known as the 'Dog alien', was introduced in the third installment of the Alien film series, aptly titled Alien³. The creature itself shares the same basic principles and instincts as the other xenomorphs shown in the previous films, although there are obvious genetic differences between a dog and a human host. When a canine is impregnated with a xenomorph embryo, its DNA is fused with that of the parasite, so the creature will have physical similarities and genetic traits of both. For instance, the Runner alien has a locomotive system that functions quadrupedally. In other words, it walks on all four limbs instead of two. It is the fastest Xenomorph subspecies seen so far. It is also an excellent climber, running on ceilings and scaling up walls at extreme speeds. Despite being smaller, less bulky without dorsal horns on its back and more streamlined than the regular variety, the Runner is more than capable of defending itself, as was shown when it dispatched an entire prison of inmates in Alien³. It was destroyed when Ellen Ripley doused it with molten lead and activated the overhead sprinklers in the furnace of Fiorina 'Fury' 161, causing the beast to literally explode from the thermal shock. In the game Aliens versus Predator: Extinction, Runners were said to have very high pressure circulatory systems that exploded when exposed to intense heat such as a flame thrower or laser.

The Newborn was the result of an artificial hybridization and was only seen in Alien: Resurrection. Its appearance is half human. Obvious human features are that it has an upright bipedal stance, an internal skeleton, a long tongue and an almost humanoid face (or more like a human skull). It is covered in moist, pinkish-white skin. The Newborn is roughly 2.4 m (8 feet) tall, but it has a slightly humped posture and, as a result of its mutated state, its corona has grown into the top of its back. However, its size and characteristics may not have been representative of its mature state. Xenomorphs undergo drastic incomplete metamorphosis as they mature, and the only Newborn specimen was destroyed within hours of its birth. When it was born, it exhibited typical Xenomorph aggression towards humans but was equally hostile to Xenomorphs. It viciously killed the Alien Queen who gave birth to it, and then mauled a cocooned scientist to death within minutes of birth. Strangely, it seemed to tolerate Ripley's presence, possibly considering her as its true mother. Ripley destroyed the creature by flicking her acidic blood against an exterior window inside a ship's hull, opening a small hole which, nevertheless, tore the creature to pieces as it was forced out into the vacuum of space. The creature seems to have possessed human emotions, as it displayed anger, distress and affection in various situations. As the Newborn was the novel result of a unique genetic experiment, it is unlikely to be seen in any other media. The scientist it killed explained that the Queen carried some human characteristics due to the blending with Ripley from the cloning that gave Ripley xenomorph characteristics. One of these characteristics is a human womb from which this creature was born.

A Predalien is a Xenomorph born from a Predator host (or in some cases, a deliberate genetic recombination by human scientists). Owing to the Xenomorph's ability to incorporate traits from its host, Predaliens are frequently depicted with Predator characteristics such as the distinctive mandibles and "dreadlocks". Predaliens are typically stronger and more agile than Xenomorphs born from human hosts, for the same reason. The Predalien appears as a chestburster in AVP: Alien vs. Predator (2004) and the grown chestbuster appeared in Aliens vs. Predator: Requiem (2007). Predaliens have also featured prominently in the Aliens vs. Predator video game series, and originally appeared in the comic book series.

Depictions of Predaliens have been even less consistent than depictions of those born from humans. 1999's Aliens vs. Predator video game depicted Predaliens as bulkier and brownish, with shortened heads and mandibles, as well as being durable (which forces use of more powerful weaponry such as a mini-gun). Its sequel gave them a pale, whitish-gray coloration and distanced them further from the general bio-mechanical appearance of the Xenomorph species. The comic which created the predalien caste, Aliens vs Predator: Duel, depicted them as bulkier with a brown tinting, only two predator mandibles, a shorter head, and multiple quils in the place of the predator dreadlocks. The film Alien vs. Predator showed only a Predalien chestburster, which was distinguished from other chestbursters in that film only by its characteristic mandibles. In Requiem the Predalien appears sporting the Predator's trademark "dreadlocks" and mandibles. It also has the strange ability to implant Chestburster embryos into the mouths of its victims. The Predalien can also implant multiple eggs into a host. Also, where normal xenomorphs are shown green on a Predator's mask display, Predaliens are yellow. This may be because of a different electrical output is produced by the Predalien than most xenomorphs possess.

While the Chestburster is still in an embryonic stage, it uses the host's DNA to augment its own and acquire any useful traits that the host has garnered through natural selection. The Aliens of the first two films were all implanted in humans and could walk in a bipedal fashion. The "Runner" of Alien³ was recognisably different from those that appeared in the first two films. It preferred to move in an animal-like manner, often running at a high speed on all four legs. This was because it wasn't conceived through a human body, but from an unlucky dog that happened to find the facehugger in the crashed lander. This new breed was far more streamlined and aerodynamic in appearance. Aside from its main appearance in Alien³, the Runner has also appeared in the video games Aliens versus Predator 2 and Aliens versus Predator: Extinction.

The Xenomorphs of the fourth Alien film, Alien: Resurrection, are an exception because they are far more human-like. The Alien queen even gives live birth to a human-alien hybrid. This is because these Aliens are the result of cloning experiments by the military, not a result of the normal implantation process. Therefore, they are not the true form of the species, having been spliced with substantial amounts of human DNA when the deceased Ellen Ripley was brought back to life via the advanced process of cloning. She was impregnated at the time of her death, which is why the Xenomorphs from the fourth film have many human traits.

In various comics and the Aliens vs. Predator video game series, this is taken a step further when an Alien embryo is implanted into one of the Predators (Predator). The result is an Alien with Predator characteristics - a so called pred-alien. This hybrid is bipedal, and has the basic body-outline of a Predator, having lost the elongated head shape. It has the inner jaw characteristic found in Xenomorphs, and a set of mandibles reminiscent of those found in the Predator. Its head also sports the dreadlocks, reminiscent of most Predators. This motif is also repeated at the end of the Alien vs. Predator film and in the new Aliens vs. Predator: Requiem film. Other comic books have shown further Alien crossovers with other species.

The origin of the Xenomorphs are never fully explained in the films. In the Alien DVD commentary, Ridley Scott merely states that the Aliens may have been bio-weapons used by the ancient race that the "Space Jockey" belonged to. The Expanded Universe indicates that more than just one of the Space Jockey's race remains alive, though their civilization is in ruins. An unknown amount of time later, the Xenomorphs are discovered by the Predators, a race of trophy hunters. The Predators then exploit the Aliens, considering them the prey used in the "Blooding" ritual or the rite of passage for young hunters.

A similar theory is briefly expounded in the spin-off novel Aliens: The Female War, suggesting that the Xenomorphs were originally engineered as weapons for a long-forgotten war, and speculating that their creators lost control of them.

The comic books speculate that the Space Jockey's race or other alien race might have taken the aliens away from their home planet. Without their natural predator, the aliens were capable of infesting other planets.

Another alternative theory presented through the Aliens vs Predator comics is that the Xenomorph is a genetically engineered being, created by the Predators for use as training and as a way to let young pre-hunter Predators go through a trial by fire to gain their status as hunters, and thus being allowed to go on hunts such as in the first Predator movie. This is especially implied in the first Alien vs Predator comic book, since the planet of Ryushi was seeded by Predators in order to go on an arranged hunt with their young hunter-students.

Dan O'Bannon, who created the Alien, wrote that the planet on which the Xenomorphs were found in the films was in fact its home world, but that a cataclysmic event millennia prior had wiped out all the adults of the species, leaving only the eggs. The creatures, prior to extinction, had reached a level of intelligence where they were able to construct temples and had their own culture and written language. The Space Jockeys, miners exploring the area much like the Nostromo and its crew, then found the planet, only to come to grief when they came across the dormant eggs. This was written into the original script, and was published in the Alien Portfolio, which detailed design aspects of the film.

• A Xenomorph appears in the Robot Chicken episode "A Piece of the Action" where it is seen playing checkers with the Predator. Mila Kunis voices a Xenomorph named Susan in the episode "The Sack" where she is on a date with a Predator named Douglas.

• In the South Park episode "Imaginationland Episode II," a Xenomorph was among the evil characters that invade Imaginationland where it killed the Mayor of Imaginationland.

• List of variations of the Xenomorph not given in the films
• Aliens (comic book)
• Space Jockey
• Predators—The alien race from the film Predator

• Alien - Released on May 25 1979 - On-line script. Retrieved 02 March 2007.
• Aliens - Released on June 18 1986 - On-line script. Retrieved 02 March 2007.
• Alien³ - Released on May 22 1992 - On-line script. Retrieved 02 March 2007.
• Alien: Resurrection - Released on November 26, 1997 - On-line script. Retrieved 02 March 2007.
• Goldman, Willie. "Sideshow Collectibles, Inc". HAIL to THE QUEEN. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
• Nathan. "PlanetAVP.com". Alien universe. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
• Internet Movie Database. "IMDb.com". Awards for Aliens. {{cite web}}: Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
• Unknown author (Last updated 2002). "Alien Collectors Homeworld". Xenomorph.org. {{cite web}}: |author= has generic name (help); Check date values in: |year= (help); Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)CS1 maint: year (link)
• Unknown author. "Predalien". Predalien information. {{cite web}}: |author= has generic name (help); Unknown parameter |accessmonthday= ignored (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
• Aliens versus Predator (computer game).
• Aliens versus Predator 2 (computer game).
• Aliens Colonial Marines Technical Manual, HarperCollins 1996, ISBN 0-06-105343-0.
• Aliens: A Comic Book Adventure (computer game) [1]

• H.R. Giger online - A website about the creation of the xenomorphs' body.
• Serena Dawn Spaceport - An Alien RPG
• The Alien Universe Timeline and Encyclopedia - © Scott Middlebrook
• Knightmare6.com, Aliens FAQ
• The Anchorpoint Essays