Headcrab

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A headcrab is a fictional alien parasitoid found in the "Half-Life" and "Half-Life 2" computer game series created by Valve Software. Headcrabs are also referred to as head-humpers by Barney Calhoun and parasitics by the Combine Overwatch. They are the most numerous and arguably most iconic aliens in the series.

At present, there are three different headcrab variations (two of which were introduced in "Half-Life 2"), all possessing the ability to attach to humans and transhumans to form zombies. While appearing similar to the original headcrab, both headcrab variations differ in a sense that they strictly use their four longer limbs for movement, attacking and standing, as opposed to the generally shorter limbs from the original headcrab.

They are ranked tenth on "EGM"’s Top Ten Badass Undead. [Scott Sharkey, “EGM’s Top Ten Badass Undead: Thriller Night,” "Electronic Gaming Monthly" 233 (October 2008): 106.]

Standard headcrab

Physical description

Often referred to as a normal, original, or classic headcrab to distinguish it from the other two headcrab species, the standard headcrab is a small creature consisting of a rounded body with four legs for movement (two stubby legs at the front, obscured by its claws, and two legs at the back; see picture) and a pair of larger frontal claws for attacking prey or as additional support when standing still. Under the headcrab's body is a large rounded mouth surrounded by pointed flesh (which also includes the headcrab's stubby front legs) with sharp claw-like "beaks." Standard headcrabs have a mottled tan-coloured skin and reddish legs.

In "Half-Life", the standard headcrabs are shown to be the offspring of a giant creature named Gonarch (also known as "Big Mama"), which shares similar physical qualities with headcrabs. Underdeveloped "baby" headcrabs spawn at a rapid rate from a sac that dangles beneath the creature.

The design of the headcrab changes between "Half Life" and "Half Life 2", with the original headcrab having exposed teeth and intestines at their mouth, while the "Half Life 2" version does not. As such, it is initially apparent that the headcrab only walks with its large front claws and hind legs, while the stubby legs form part of the headcrab's mouth. The headcrabs found in "Half-Life" are also noticeably smaller than those in "Half-Life 2", which have bodies approximately the size of a watermelon. The description for the plush headcrab collectible item indicates that the six-inch toy is quarter-scale, meaning that a normal-sized headcrab is typically two feet in length.

"Half-Life" and "Half-Life 2" also oppositely depict the headcrab's tolerance to water and toxins: while headcrabs in "Half-Life" can swim but die in toxic environments, headcrabs in "Half-Life 2" drown instantly in deep water but easily survive in contaminated pools. The headcrab's resilience towards toxic and radioactive materials appears to be passed on to their hosts, as zombies are frequently found in conditions that would otherwise be hazardous to their hosts.

The games also establish that while headcrabs are parasites that prey on humans, they are also prey to the creatures of their homeworld. Bullsquids, Vortigaunts, and barnacles will all eat headcrabs (it should be noted that the barnacles will eat whatever they can grab); Vortigaunts can be seen cooking them on several occasions. Even humans will eat headcrabs, though they are apparently not fond of the taste ("they don't taste like crab", a human comments in "").

Behavior

By itself, a single standard headcrab is of little threat to the player or anything else. They are relatively slow-moving and their attacks inflict very little damage. In addition, they can be killed very easily; a single swipe of the player's crowbar or a few bullets are sufficient to dispatch any variant. The headcrab's only advantage is in its ability to leap surprisingly fast over great distances. In flight, it tilts upwards to have its mouth face its target, attempting to attach itself to its target in order to control it.

Headcrabs have a penchant for lying in wait in dark corners and ventilation shafts. In more open environments, headcrabs are known to bury themselves in the ground to hide, then climb out to the surface and attack when a victim draws near. Headcrabs are often seen clustered in groups to make up for their individual weakness. They pursue their prey with single-minded determination, never fleeing despite the death of fellow headcrabs or any other dangers.

Headcrabs can produce a variety of vocalizations. When they are not hunting, headcrabs usually emit squeaks and fairly quiet, repetitive calls while gently swaying their bodies back and forth. When attacking, headcrabs emit a sharp, shrill shriek as they leap towards their victims. When a zombie it attaches itself to dies, occasionally the headcrab will detach from the dead body, probably in search for a new victim.

Fast headcrab

The fast headcrab, alternatively named the spider headcrab, is introduced in "Half-Life 2". This version, though similar in color to the standard headcrab, has long, spider-like legs, which allows it to move much faster. It does not have a "beak" like the other varieties, instead using the sharp talons at the ends of its legs to latch to hosts. It is also capable of clinging to walls and ceilings using its talons, an ability first seen in "". Strangely, whenever the player encounters a zombie this headcrab has taken control of, the zombie has no skin, very little flesh, and exposed bone. This may have possibly led from digestion of the body. Like the headcrab itself, these zombies are very fast, and are able to leap large distances.

Poison headcrab

The poison headcrab (also known as black headcrab and venom headcrab) is also introduced in "Half-Life 2", shortly after the fast headcrab. This version is identifiable by its dark sage green color skin (sometimes with a wet shine, attributable to a lighting problem with "Valve's" "Source" engine) and thick hairs on the joints of its inward bending legs. To distinguish it further it has white bands that encircle its knee joints. It also makes a chirp at range and a hissing/rattling similar to that of a rattlesnake's tail when it detects a viable host. Unlike the other headcrabs, the poison headcrab has some survival instinct, as it will retreat when injured. It is worth noting that poison headcrabs react to water in the same way as an antlion: they die after a while when submerged.

A poison headcrab will move slowly and cautiously when maneuvering, but like the other headcrabs will quickly leap with an angry squeal when it has a clear line of sight to a potential host. At walking pace, the poison headcrab is the slowest of the headcrabs, but will run much faster than a normal headcrab if injured. Several poison headcrabs will group together on a single host once one is found; the attacking poison headcrab controls the host while the others use the new host as transportation. Since poison headcrabs are the slowest of the headcrabs, they have adapted by having the host throw them at new victims. It should be noted that the hosts of "poison" headcrabs are quite swollen in an unnatural way.

The most notable aspect of the poison headcrab is its namesake neurotoxin delivered from four fangs on its "mouth": in one attack this neurotoxin will reduce the player's health to one hitpoint, regardless of the current health amount or HEV suit charge. However, assuming the player is not injured further, the HEV suit will provide an antidote, restoring the player to their original health total (minus that of the damage inflicted by the headcrab) at intervals of ten points every two seconds. The attack also reduces the HEV suit's charge (if any), which is not restored. While this makes it next to impossible for even a large group of poison headcrabs to kill the player, it does make fighting other enemies at the same time (other headcrabs, zombies, Combine, etc.) far more dangerous. Notably, getting a barnacle to devour a poison headcrab will paralyze it temporarily. According to "Half-Life 2: Raising The Bar", the development team noticed that upon hearing the poison headcrab's cries, playtesters would frantically start looking around for the poison headcrab so they could destroy it, regardless of any other present dangers.

Headcrab zombie

A headcrab's primary goal is to attach to the head of a suitable host using its mouth (typically covering the face and most of the head). The headcrab then burrows its claws and hind legs into the host, whereupon it takes control of its victim's body, rendering the unfortunate individual a mindless zombie-like being known as a headcrab zombie, or "necrotic" as the Combine Overwatch calls it.

Once the headcrab is attached, it opens up portions of the skull with its mouth. By incorporating parts of its biological workings with the motor cortex of the host's nervous system, it is able to utilize motor functions of the host.

Interestingly, no Xen species are seen infested with headcrabs though it has been said that Xen is not the original homeworld of most of these species. [Marc Laidlaw [http://www.halflife2.net/forums/showpost.php?p=1994259&postcount=847 e-mail about Alien Controllers] , halflife2.net forum] Lamarr, Dr. Kleiner's pet headcrab, is fed watermelons, which suggests that headcrabs are omnivores.

Like standard headcrabs, both fast headcrabs and poison headcrabs are also capable of attaching to a host's head, although these headcrabs each induce different forms of mutations on their hosts and the resulting zombies employ different strategies of attack. An unusual characteristic of both zombie variations is that only three middle fingers of the five on each zombie's hands develop into claws, compared to all the fingers on a standard headcrab zombie. In addition, neither two variants have a describable "maw" nor the chest cavity that normal headcrab zombies possess, although fast zombies do have cracked rib cages and seemingly no internal organs, creating a hollow space.

In most cases, a headcrab remains attached to its host until destroyed. In "Half-Life 2", however, they have the ability to abandon their host if it is wounded significantly. Removal of the headcrab reveals that the host's face and head has been eaten away by the creature; the degree of such damage on these areas depends on the type of headcrab in control (for example, a standard headcrab zombie will have, at most, have a pale distortion to their face and blood spewed at the ends of their hair, while a fast headcrab zombie will have only their skull visible).

In Half Life 2 Headcrab zombies, for the most part, tend to be found in more secluded areas (for example: in disused tunnels, abandoned buildings, in caves, cliff cavities, etc.). These areas will often be near sites that have been shelled with Headcrabs by the combine. If zombies stray into open, more populated areas they tend to be (unsurprisingly) shot (the player witnesses a Combine sniper shooting a zombie that appears to have strayed out of the mines of Ravenholm).

Standard headcrab zombie

When a standard headcrab successfully attaches to a host, the host becomes a standard headcrab zombie. The headcrab's alien physiology causes various mutations to rapidly manifest in its host, giving it elongated claws, increased strength, and what appears to be a sharp-toothed "mouth" that bisects the victim's chest cavity from neck to groin. This giant mouth has inspired the nickname "Mawmen". In "Half-Life 2", their appearance is slightly different; the "teeth" of the mouth are clearly revealed as protruding ribs: a ripped open chest cavity and no sternum. The official Prima game guide for "Half-Life 2" still mentions the "Mawmen" nickname. In the original "Half-Life" zombies can be seen tearing flesh from corpses and feeding it into their "mouth". An effect that signals a zombie's presence in the run-down areas of City 17 is the buzz of flies, showing that the corrupted body of the victim is rotting.

The standard headcrab zombie can be detected by the moaning sound it makes when moving and by the growling sound it makes when it detects the player in its presence. Once it detects a victim, it slowly and purposefully edges its way towards them, using its claws and enhanced strength to beat them to death. Because headcrab zombies are slow, they are often found in confined spaces and/or in large numbers to compensate. In addition, standard headcrab zombies will often feign death until the player approaches, catching them off-guard. In "Half-Life 2", they can swat loose objects on the ground when they run into them, creating potentially lethal projectiles. Some of the zombies encountered in the game have no body below their waists; they crawl around with their arms and swing at the player. Though slower, these half-zombies are harder to approach because their arms are already poised to attack, whereas "whole" zombies take a few moments to prepare a strike.

Gonome

The gonome is apparently the next step of a standard headcrab zombie's mutation. It is larger, stronger, and more intelligent than "ordinary" zombies; it also produces a volatile saliva (similar to that of a bullsquid) that the creature can retrieve from its chest "maw" and throw as a weapon. Gonomes can create lairs, or "nests", for themselves with enough time. Gonomes appear only in the expansion pack "".

Fast headcrab zombie

When a fast headcrab attaches to a host, it produces a fast headcrab zombie. These zombies are stripped of their outer skin, some body tissue, and most or all organs, leaving large parts of the victim's skeleton exposed. They retain the elongated claws like the normal headcrab zombies. They can not only run, but also jump great distances and rapidly climb rain gutters. They also move on all four limbs, but stand on two legs when attacking a victim.

Fast zombies, if not visually detected well in advance when leaping across buildings, betray their presence with the ear-piercing scream they let out when they attack. A fast headcrab zombie's usual method of attacking, when given a clear distance to its prey, is to leap forward several yards to tackle and claw it into the ground. Despite their speed and physique, fast zombies are quite weak, and many claw strikes can be endured before the player dies. Though they are not as numerous as standard zombies, they often attack in groups of two to three. Also, they sometimes group with other headcrab zombies. In "Episode One", fast zombies also come in a torso-only variant, and are still much faster than other zombies.

Poison headcrab zombie

Poison headcrabs produce the poison headcrab zombie, a bloated, reddish/purplish, slow-moving and hunched-over "carrier" for other poison headcrabs. It is the strongest and most resilient form of headcrab zombie in terms of damage capability and overall health. However, the extra weight makes the poison zombies move a lot slower. It should be noted that when (or after) killing the poison zombie in "Half-Life 2" the host is missing most of the skin on its back, thereby revealing its spine, the former of which was probably eaten by the initially carried headcrabs.

A poison zombie reveals its presence with its distinctive, strangled, heavy breathing and muffled moans. Despite being created from a poison headcrab, poison zombies cannot directly poison others and attacks with its claws. Though the poison zombie can do great damage this way, its most dangerous weapon is the extra poison headcrabs it carries, which it can throw at the player.

Zombine

"" introduces headcrab zombies created from transhuman Combine soldiers. Alyx Vance coins the term "Zombine" for them as a portmanteau of "Zombie" and "Combine". Only Zombines controlled by normal headcrabs appear in "Episode One" and "Episode Two". The introduction of the Zombine enemy was meant to show that, in the wake of the devastation caused by the player in "Half-Life 2", what was once a valuable weapon in the Combine arsenal is now just as dangerous to them as humans."Half-Life 2: Episode One", Chapter III: Lowlife, Developers commentary [2006] ]

In terms of physical characteristics, a Zombine is more built than the standard headcrab zombie due to the cybernetic implants on the victim beforehand. The differences lie in what the victim was wearing at the time: the body armor of the Combine soldier still covers the Zombine's body, hiding the chest and mouth and making them harder to kill. Removal of a Zombine's headcrab reveals that, aside from the lower jaw and small lower portion of skull, no head or helmet remains on the soldier's corpse. The official Prima strategy guide for "Episode One" indicates that the lack of a head is meant to be an intentional mystery, but also suggests that headcrabs do not require a brain to connect to their host. These Zombines also lack the elongated claws of their counterparts. Zombines sometimes have "speech" which is composed of zombie growls and Combine soldier reports, such as "Necrotics inbound" or "Sector's not secure".

Zombines, like regular zombies, groan constantly, in an electronically modified voice. Zombines move faster than normal headcrab zombies (capable of short sprints), but slower than the fast variety. They do more damage than their normal counterparts and are more resilient as well, owing to their genetic enhancements and armor. Aside from their regular attack, Zombines are notorious for their unique tactic: they will stop in the middle of a fight, procure and prime a grenade, then charge in a kamikaze-attack, seemingly unaware of the grenade's danger but still familiar with its use. The player may pull the live grenade out of a zombine's hand by using the gravity gun.

Lamarr

Introduced in "Half-Life 2", Lamarr is the domesticated headcrab belonging to Doctor Isaac Kleiner. Having been debeaked, thereby eliminating her ability to attach to and control a host, Lamarr has been rendered into a semi-tame pet for Kleiner and a nuisance to anyone else she comes into contact with. Kleiner states that "the worst she might do is attempt to couple with your head…fruitlessly," behavior that leads Barney Calhoun to dub her "freakin' head-humper." Lamarr is named after the late 1930s actress and inventor Hedy Lamarr, as evidenced when Dr. Kleiner alternatively calls her "Hedy" in the conclusion of the chapters "Red-Letter Day" and "Entanglement".

Lamarr serves as the catalyst for the first few chapters of the single player campaign in "Half-Life 2". When Gordon Freeman attempts to use Kleiner's teleporter, Lamarr jumps from a vent and damages it while Gordon's teleport is in progress, forcing Gordon to proceed on foot once the malfunction subsides and leaving Lamarr in the desert to chase crows in one of the accidental destinations of the teleport. When Alyx and Gordon return to the lab some time later, Lamarr has returned and Alyx has to stay behind to help Kleiner catch her, as Kleiner refuses to leave without her. Lamarr makes her final appearance in "Half-Life 2" after the credits, dropping down into a black background and then leaping towards the screen as part of a stinger sequence. Lamarr is safe and sound in "Episode One", where she makes a brief cameo appearance, causing further mischief to Dr. Kleiner during his live and unedited evacuation broadcast in City 17. She makes yet another appearance in "Episode Two", where the player can see her climb into Dr. Magnusson's rocket, which is launched shortly before the end of the game. Seconds before the launch, Dr. Kleiner notes a payload anomaly of approximately 8.5 pounds, suggesting that Lamarr has been launched into space.

Use as biological weapons

While headcrabs are merely wild parasites in "Half-Life", "Half-Life 2" shows that the Earth-occupying Combine alien race have put them to use as an unstable but effective biological weapon against the human Resistance. By storing several headcrabs into "Headcrab shells", man-sized projectiles fired from a mortar-like launcher (only one is featured, in "", but there would presumably be more for such a weapons system to be effective), the Combine can bombard distant areas with them. The payload of each shell is released into the open shortly after impact, free to infest or kill nearby victims without risk to the Combine forces. As in the unfortunate case of the devastated town Ravenholm, repeated bombings can neutralize entire towns in a short space of time.

Headcrab shells commonly carry standard headcrabs and fast headcrabs, as can be seen throughout "Half-Life 2"; poison headcrabs are only seen emerging from headcrab shells during the church battle in "Half-Life 2: Lost Coast" and in the "Exit 17" chapter of "". The only example in "Half-Life 2" is where the player can enter a house which has been bombed by a headcrab shell during the "Highway 17" mission. Searching the house will reveal several poison headcrabs and a poison headcrab zombie, but no other types, indicating that the shell contained poison headcrabs. The number of headcrabs in a missile varies between species of headcrab.

Merchandise

In order to fulfill their fans' demand for headcrabs, Valve released a plush headcrab for sale at the [http://www.store.valvesoftware.com Valve Store] . It featured posable limbs, a number of teeth and claws and a gaping maw. The headcrab went out of sale within a few months. For a 2006 Christmas special, along with the re-release of the plush headcrab, fans could buy a headcrab hat, specially designed to give the impression that the wearer is under attack from the parasitic alien.

imilarities to other fictional creatures

The headcrab is very similar to the facehugger in the "Alien" movies, as both have no visible eyes and must leap onto their host. Although their purposes for their hosts are different, there are many similarities between the creatures. For example, the fast headcrab zombie is similar to the Runner or Dog Xenomorph. The brainsucker aliens of ' are small four-legged yellow creatures that leap onto a victim's head, though brainsuckers fall off and die following a successful zombification. The Flood parasite from the "Halo" video game series are also similar to headcrabs, to the point that some new players refer to the Infection Form as "headcrabs". Remotely similar to the headcrabs, the Flood parasites send needle-like tentacles into the victim's neck to control the victim via the spinal column, though they are filled with flammable gas and explode violently when killed. They also turn their victims into zombies, although they act more intelligently, using firearms and vehicles. They too, have many different forms as of "Halo 3". Though the first ' game was released after "Half-life", the conceptual genesis of the Flood actually pre-dates Half-life with Bungie's earlier game "" as can be seen in some of the concept art for that game. [cite web |url= http://www.bungie.net/projects/marathon/asset_popup_viewer.aspx?at=51&cc=33&item=2|title= Marathon Series Concept Art|accessdate=2007-11-09 |format= HTML and JPEG|work= Concept art by Robert McLees] The headcrab's parasitic ability is also speculated to be inspired by the capability of the Emerald Cockroach Wasp to paralyze and control "zombie" cockroaches, in a manner that could be similar to how a headcrab controls its host [http://loom.corante.com/archives/2006/02/02/the_wisdom_of_parasites.php] . According to backstory on Blizzard's website, the first Zerglings were created when Zerg larva burrowed into their spinal columns, subverting control of the animal and eventually incorporating its genetic material into the Swarm, though this has since been supplanted with the Zerg hyperevolutionary virus. The Metroids from the Metroid series are very similar in behavior and appearance, aside from being permanently airborne, and the fact that they are vampires rather than parasites, although they're always described as parasitic life forms.

Similar plot devices are used though fiction such as in Ian Livingstone's Fighting Fantasy book "Island of the Lizard King", involving a creature called a "Gonchong" whose proboscis would burrow into the head of a host to control it, Clark Ashton Smith's short story "The Vaults of Yoh-Vombis" features slug-like creatures that eat away human skulls, then control their victims through neural stimulus; unlike the Gonchong, the headcrab does not actually bury into the skull of the host. In the Star Trek film "", Ceti eels are used. In all these examples an animal is used to control the thought and or actions of a human host. In the Science Fiction/ Horror FPS System Shock 2 parasitic worms attached to most of the crew's necks allow them to be controlled by a hive mind.

References