Xenomorph XX121 (Alien)

**Xenomorph XX121**,commonly referred to as simply the **Xenomorph** and known colloquially as the **Alien**, is a highly aggressive endoparasitoid extraterrestrial species. The Xenomorphs are vicious predatory creatures with no higher goals than the propagation of their species and the destruction of any life that could pose a threat to them. Like wasps or bees, Xenomorphs are eusocial, with a fertile Queen breeding a host of subordinate castes. The creatures are known for their potent acidic blood and their pharyngeal jaws, although their biological life cycle, in which their offspring are implanted inside living hosts before erupting violently from their chests, is in many ways their signature aspect.

## Biology

### Distinctions:

Vicious predatorsAcid bloodEndoparasitic reproduction

## Characteristics

Xenomorphs are primarily solitary ambush predators, although they have been known to adopt swarm tactics when acting in larger groups. Despite their voracious ability to kill, they often seek to take their victims alive to be hosts for more Xenomorphs; victims are taken to the Hive (or simply a secluded location if no Hive exists), cocooned and/or immobilized before being impregnated with a Xenomorph embryo. However, when their target becomes a threat or is deemed unsuitable for harvest, the Xenomorph will not hesitate to quickly dispatch the chosen host.

### Appearance

Notably, Xenomorphs will alter their physical appearance during development depending on the physiology of the host in which they gestate — in all likelihood, this incorporation of physical traits gleaned from the host is designed to ensure the adult creature is better suited to the environment in which it will find itself. This ability to alter its form based on the host's physical attributes occurs at a cellular level and has been referred to as the "DNA reflex".[6] Historically, most Xenomorphs encountered have typically gestated inside human hosts, and therefore adopt a basically bipedal, humanoid stance, but other variations born from a wide variety of different host organisms have been seen, and as a result feature varying physical appearances.However, regardless of any physical variation resulting from the host, Xenomorphs always possess certain distinctive, trademark characteristics.

Outwardly, they are encased in a tough mesoskeleton, lending them a skeletal, biomechanical appearance, and are usually colored in muted shades of black, blue or bronze. The outer shell is incredibly resilient, impervious not only to the creature's own potent acid blood, but also capable of withstanding some forms of small arms fire. Whatever organism a Xenomorph gestates within, they invariably possess distinctive, elongated, cylindrical skulls, but have no visible facial features other than their mouth. The carapace atop the head has been seen to vary, from smooth and vaguely translucent to ridged and opaque. It has been proposed that this difference is part of a maturation process, and that younger Drones possess the smoother, domed carapace, while older ones feature ridges. Notably, ridges are often visible beneath the smooth dome of Drones.

The Xenomorphs' primary weapon is their inner pharyngeal jaw, which is capable of shooting from their mouth like a piston with sufficient power to smash through bone and metal.[8][5] In fact, a common tactic used by the creatures to eliminate prey is to restrain the victim with their hands, immobilizing them, before killing them with a precision jaw strike to the head, piercing through the skull and penetrating the brain; this form of attack is colloquially known as a "Headbite".[9] On several occasions, Xenomorphs have been seen to suspend the corpses of those that they kill from ceilings.[8][10]

Xenomorphs have segmented, blade-tipped tails. The sharp tip has been seen to vary from a small, scorpion-like barb[8] to a larger, flat blade.[5][11] Despite their seemingly flimsy physical construction, the creature's tail makes for an incredibly potent weapon, strong enough to impale and lift a Yautja from the floor with seemingly little effort. The tails have been used variously as stabbing, slashing and blunt force trauma weapons.[8][11] Above the tails, the creature possesses several dorsal spines on its back, typically consisting of two pairs — a larger upper pair and a smaller lower pair — often with a fifth, sharper spine in the centre below the base of the head. The exact purpose of these tubes is unclear.

As a result of the DNA reflex, Xenomorphs have appeared as both plantigrade and digitigrade organisms, usually in accordance with their host. For example, human- and Yautja-spawned Xenomorphs typically possess humanoid hind limbs and walk upright, while Xenomorph's spawned from quadrupedal hosts (referred to as "Runners") sport double-jointed hind legs and move predominantly on all fours. The Cloned Xenomorphs created aboard the USM *Auriga* also possessed digitigrade legs despite spawning from human hosts, perhaps as a result of imperfections and cross-contamination in the cloning process.

### Physical abilities

When standing upright, Xenomorphs are vaguely bipedal in form, though they adopt a more hunched stance when walking or sprinting and are equally adept at moving on all four limbs, even in instances where the host was a bipedal lifeform, such as humans. They are quite capable of running and crawling along ceilings and walls] and are expert jumpers. They possess great physical strength, having been known to break through metal vent covers and welded steel doors with little effort, and even of breaking down reinforced pressurized doors over time. Their large clawed talons are more than capable of tearing humans apart, while their primary jaws are capable of producing a bite strength estimated at 6,000 psi.

Xenomorphs do not radiate heat, and their body heat matches the ambient temperature of the environment in which they are found. They are also impossible to lock on with a Standard Transporter Signal, a tracking device needs to be placed onto the body of the creature to be able to Lock on to it, and even then the Creature must not be moving at a Fast Pace for the lock to work. Adverse extremes of temperature appear to have little, if any, affect on their physical prowess. In fact, physiologically they are incredibly hardy creatures — aside from being unaffected by temperature extremes that would quickly incapacitate or kill a human, they are capable of surviving in the hard vacuum of space, at least for a limited period of time. In order to succeed in their attack on enemy human vessels, the Rage equipped attacking Xenomorphs with breathing apparatus, suggesting that the creatures do require some form of atmosphere to survive for extended periods in space. One Alien on Fiorina 161 was even known to survive several tons of molten lead being poured onto it.

### Senses

Xenomorphs notably lack lens-based, photosensitive visual organs. However, studies by Starfleet have shown that they nonetheless possess several keen senses. First and foremost, the creatures have sensory structures along the sides of their extended skulls that are capable of perceiving atmospheric vibrations (sound). Given the lengthy structure of the head, which gives the creature a wide field of "hearing", this is thought to be the Xenomorph's primary means of rationalizing its environment, a form of biological sonar similar to that employed by terrestrial bats. The creatures are also capable of detecting heat via highly sensitive thermoreactive organs located behind the skull's frontal plate — which is itself constructed of the unusual C60 carbon-lattice, known to demonstrate exceptional conductive properties. This, coupled with a highly developed olfactory sense, is thought to be how Xenomorphs locate their prey. Their sensitivity to pheromone signals would also help to explain why the Yautja Cloak is ineffective against them. Finally, despite the absence of traditional ocular organs, Xenomorphs possess largely vestigial photosensitive organs flanking the frontal plate; these rudimentary visual receptors are thought to grant the creature the necessary depth perception required when attacking prey. It is possible they also aid the creatures in seeing each other, as Xenomorphs produce no notable body heat, a fact that would otherwise render them blind to their thermal receptors.

During tests,Starfleet Intelligence personnel discovered that it is possible to stun Xenomorph specimens through the use of a low-intensity ultrasound pulse, rendering them completely inert and relatively safe for manipulation and study. This discovery led to the development of weapons effective at disabling Xenomorphs, such as the Sound Cannon.

According to the research of Dr. Paul Church, the Xenomorph has a "psychic receiver" organ at the front of its head lined with compound cells of fullerite-encased hurlantium. The internal structure is solid neurons in two binary very dense fans. The fullerite and hurlantium pick up E-waves and the binary fans create interference patterns from electromagnetic fields. This allows the Alien to receive brainwaves and enables it to assess another animal's physical characteristics by seeing its subtle body. That is why strong electromagnetic fields affect the Aliens.

Furthermore, this organ atrophies when the Alien is in captivity.

### Blood and secretions

Xenomorph blood is an extremely potent and concentrated molecular acid that can corrode on contact almost any substance with alarming speed. It is dull yellowish-green in color. The blood is in fact a component in a biological "battery" that provides the creatures with their energy,and seems to be pressurized inside the body so that it spurts out when wounded, as a defensive measure. This blood can prove incredibly problematic when encountering Xenomorphs aboard a starship, as using traditional weapons or explosives to attack the creature will potentially cause its blood to leak out in sufficient quantity to eat through the hull of the ship.

In some instances, Xenomorphs have been known to be conscious of the effects of their acidic blood, and even exploit it to their advantage — aboard the USS *Auriga*, the Lead Alien and another Xenomorph successfully escaped their containment cell by eviscerating a third, causing its acid blood to melt through the floor of the cage. Some forms of the Xenomorph have been known to "spit" acid, either as a tool or a form of attack. For example, Facehuggers have been known to regurgitate a small amount of acid to melt through obstructions between them and a potential host, such as the faceplate of a spacesuit helmet.[8] This spitting ability has also been exhibited offensively by adult Xenomorphs; much like a spitting cobra, the creatures will spit acid to blind and incapacitate their victims rather than kill them outright.Despite their own immunity to their blood, Xenomorphs are vulnerable to hydrofluoric acid, which was used against them to great effect on LV-178.

Xenomorph Drones can also produce a thick, strong resin (vomited from their mouths) that they use to build their Hives and to cocoon their victims. This substance has the added effect of paralyzing their victims when regurgitated over their nose and/or mouth, making it easier for the creatures to move them to the Hive for implantation.

### Intelligence, communication and behavior

The Xenomorph's level of sentience is a matter of some debate.However, it is clear that they are clever and tenacious hunters. Moreover, the Hadley's Hope and USS *Auriga* incidents both showed that the species excels at observational learning and problem solving. In both cases, Xenomorphs managed to learn how to operate the machinery of their mechanized environments at a very basic level.

It has been theorized that the intelligence of individual Xenomorphs may be influenced by the host.

The means by which Xenomorphs communicate amongst themselves is unclear, although it is apparent from their behavior that they possess the ability to do so. While Xenomorphs are able to vocalize a variety of hisses and screeches, it seems probable that the majority of their communication is performed through some other means, possibly involving the use of pheromone release or ultrasound. Starfleet scientists have gone as far as proposing the creatures are bioelectrically "networked" in a collective hive consciousness, allowing for near instantaneous communication, simultaneous learning and unified action among all the individuals in a Hive.

They make few vocalizations beyond snarls and high-pitched shrieks when in pain or attacking. They regularly hiss while active, but are otherwise silent, particularly when stalking prey.

According to the research of Dr. Paul Church, the Alien also has an enormously complex neurological structure in the dorsal region of its head. He suspected this is what the Alien has instead of a brain.

### Sex

The question of the Xenomorph's biological sex is heavily debated. However, the preeminent theory is that the species is hermaphroditic

### Diet

Little is known regarding the Xenomorph's diet. The fact that their blood generates the energy they use to power their bodies means they may not require traditional sustenance at all. Events at Hadley's Hope on Acheron seem to imply the Xenomorphs do not use the humans they capture as a food source, as Marines who entered the Hive there found it to be littered with the corpses of colonists used as hosts, none of whom showed any sign of having been consumed, in whole or in part, despite the fact they had been cocooned for some time. Similarly, Marines from the USS *Sephora* found evidence that even bodies left cocooned for as long as 17 weeks were not desecrated or devoured in any way following death.

## Life Cycle

The Xenomorph life cycle is a complex process comprising several distinct stages. The creature begins its life as an Ovomorph, or Egg, laid by a Queen, which hatches a parasitoid larval form known as a Facehugger, which in turn "impregnates" a living host with an embryo known as a Chestburster. After a gestation period of several hours, the Chestburster erupts violently from the host's chest, resulting in the death of the host. The Chestburster rapidly matures to an adult phase (within a matter of hours or even minutes in some cases), shedding its skin as it grows and replacing its cells with polarized silicon. Due to the DNA reflex, horizontal gene transfer during the gestation period leads the adult Xenomorph to take on some of the basic physical attributes of the host from which it was born.

The Xenomorph life cycle bears similarities to that of certain parasitoid insect species found on Earth. Its use of a living host as an incubator for the developing infant is arguably the creature's most well-known physical attribute.

## Society

Xenomorphs operate under a caste system, with groups of specialized individuals performing distinct tasks within the species. It is not clear to what degree these castes are subject to a social hierarchy, although certain Xenomorph types, notably the Praetorians and the Queens, clearly exercise some degree of control and superiority over other more common variations.

While individual Xenomorphs have been known to operate independently, owing to their tendency to reproduce rapidly and in large numbers they are more commonly encountered in groups and often likened to an infestation owing to their tendency to spread and consume all suitable host organisms in an area. As with many other eusocial organisms, Xenomorphs, particularly in larger groups, will create a central nest or Hive in which they will reside, often overseen by an Egg-laying Queen. Raiding parties will be sent out into the surrounding area to search for and capture more hosts, which will then be brought to the Hive and used to create more Xenomorphs. In larger infestations, smaller "satellite" Hives may be created, containing just a few Xenomorphs, allowing victims to be cocooned and impregnated even far away from the Queen herself.[24]