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Poison Headcrab

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Headcrab poison.jpg
HLA PoisonHeadcrab.png
Poison Headcrab
General information

Xen wildlife


Venomous Headcrab variation

Personal information

Poison bite (10 damage, drops the player's health to 1 instantly, which eventually regenerates)[1]

Game information
  • npc_headcrab_poison
  • npc_headcrab_black

Ted Backman[2]

The Poison Headcrab, called Venom crab by Alyx Vance, is a Headcrab variation introduced in Half-Life 2, appearing in all subsequent titles. It is utilized by the Combine via Headcrab Shells and possesses a unique neurotoxin attack.


The Poison Headcrab can be identified by its dark skin (or exoskeleton, judging by the shine it has and its high health). They have thicker legs than other Headcrabs, with bristle-like hairs. White bands circle its knee joints, where its legs bend inward. The creature's dorsal markings are similar to those of a species of orb-weaving spider (Araneus diadematus). Unlike other Headcrabs, it has only four fangs, which are uniquely curved back and hook-like. These are most likely what they use to inject their neurotoxin. It's also interesting to note how large their mouths are. They're much wider and have a pink, fleshy, rim surrounding it, unlike other Headcrab species.

Gordon's first encounter with this beast is in an abandoned house in Ravenholm, just before he flips a switch to deactivate an electrical fence in the cobblestone street below. They are rare, usually appearing only where a Headcrab Shell was previously seen. Unlike the other headcrabs, poison headcrabs have to "charge up" before striking

Behavior and skills[edit]

At a walking pace, the Poison Headcrab is the slowest Headcrab, but panics and runs away if attacked. Poison Headcrabs move slowly and cautiously when maneuvering but leap with incredible speed while releasing an angry squeal when a suitable host is in a clear line of sight. As an ambush tactic, it leaps at and poisons a viable host in an attempt to create a Poison Zombie. Poison Headcrabs make a sound similar to Rattlesnakes when searching for prey. Also, as another lure, the Poison Headcrab will make a whistling noise.


The Poison Headcrab delivers its extremely powerful neurotoxin via the four fangs on its "beak". In gameplay, the neurotoxic Headcrab venom reduces the player's health to 1% immediately regardless of the current health amount. After a period of time, the HEV Suit will provide an antidote to restore the lost health, with 10% of it being lost from the Headcrab's physical damage.

As of the 2010 update, it appears that Poison Headcrabs alone are indeed incapable of killing the player.

During the events of Half-Life: Alyx, the venom of Poison Headcrabs appears to be less potent. They do not drop Alyx down to one health when she is bitten, but they do briefly blind her. Her vision continues to be distorted slightly after the initial bite, indicating she is still experiencing some sort of toxin, but it does not persist for long. Additionally, when eaten by Barnacles the venom does not instantly kill them, unlike in previous games.

Poison Zombie[edit]

Main article: Poison Zombie

Like all other Headcrabs, Poison Headcrabs can latch onto a human's head and take control of their nervous system, creating a mindless 'zombie' that submits to the will of the Headcrab. Poison Zombies have a number of key differences from Standard Zombies, including increased health and the ability to carry 3 other Poison Headcrabs on their back.


Poison Headcrabs can be difficult to deal with, as their bite can leave you vulnerable to other enemies. Therefore, it's best to focus on the Headcrabs first, before attacking other foes. If there are Barnacles around, you can lure Poison Headcrabs into their tongues to get a quick kill and conserve ammo. However, this should not be considered a tactic in itself as it can be risky. It's better to attack these vicious creatures directly.

Poison headcrabs can be stunned and then killed with 3 blasts from the Gravity Gun. If you are not confident enough to use this method, you must keep away from the Headcrab while firing into its main body. If you are bitten, run away from the crab(s) and let your health recover.

If you are careful and in a situation that involves small rooms and large amounts of enemies (such as in Ravenholm), you can use your Crowbar to quickly dispatch headcrabs, and any weapon of choice to kill any zombies in the area.

In Half-Life: Alyx, Poison Headcrabs behave more erratically and attack much sooner than their Classic Headcrab cousins. Their bodies are large, and cannot be easily picked up, so you should be prepared to duck or dodge at any moment. If struck by their Venom, you will be temporarily blinded, so be careful not to wander into hazards or other enemies. They typically lurk in dark environments and like to hide when wounded, so checking your corners is paramount.


The Leak Poison Headcrab.
  • According to Half-Life 2: Raising The Bar, the development team noticed that upon hearing the Poison Headcrab's sound playtesters would frantically start looking around for the Poison Headcrab so they could destroy it, regardless of any other present dangers.[2]
  • It has an unused animation called "spitattack," depicting the Poison Headcrab engaging in a spitting attack.
  • The Poison Headcrab's second scream, "ph_scream2.wav", is a sped-up version of the Fast Zombie's first scream ("fz_scream1.wav", the "Howie Scream").[3]
  • If severely hurt, the Poison Headcrab will attempt to hide or run away from the player. On rare occasions, the Poison Headcrab will ignore the player and try to seek refuge in a corner or secluded area.[source?]
  • Poison Headcrabs are dangerous to NPCs such as Rebels as they lack the health regeneration necessary to counteract its neurotoxin. As a result, a hit from a Poison Headcrab will permanently reduce their health to 1, causing them to be instantly killed the next time they receive damage unless healed with a Medkit.
  • In Half-Life 2, the Poison Headcrab has a minimum distance for an attack. If the player is touching it, then it will not attack but instead crawl away to reach the minimum distance.
  • If the Poison Headcrab is eaten by a Barnacle, the Barnacle will die shortly afterwards. This sometimes will not occur.[source?]
  • There are only few sightings of Poison Headcrabs emerging from Headcrab Shells. The first instance of a Poison Headcrab seen emerging from a pod is inside a container during the Strider battle at the end of Episode One. In Lost Coast, upon jamming the Headcrab Launcher, the three canisters located next to the launcher will open, and one Poison Headcrab will come out of each canister.
  • In Episode Two, Poison Headcrabs will run when shot in all instance. In Half-Life 2 and in Episode One, the Poison Headcrab will only run when attacked while unaware.[source?]


List of appearances[edit]

Main games[edit]



  1. 1.0 1.1 Half-Life 2 Prima Guide
  2. 2.0 2.1 Half-Life 2: Raising the Bar, page 74
  3. Half-Life 2 sound files