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"There's a tranquilizer gun in the shark cage. But i'm not sure it would work on this species... you're welcome to try."
Black Mesa Scientist[src]

The Black Mesa Crossbow, also called a Tranquilizer Gun is a long range sniper weapon featured in Half-Life. It is very effective against distant targets, but is relatively less effective in close-quarters combat or against fast moving opponents due to its slow reload time and the low velocity of the shot. The primary trigger fires a bolt; the secondary trigger utilizes the scope.


In Half-Life, the Crossbow is first acquired by the player during the chapter Apprehension, where it can then be used to kill an Ichthyosaur. After the chapter, it can be reacquired in the chapter Questionable Ethics, after Gordon had been stripped of his weaponry upon capture by HECU Marines. The construction is modeled upon modern composite bows. Its ammo consists of five feathered bolts in a magazine. These are fed one at a time into the firing mechanism, which utilizes a high-tension wire to launch the bolt; while a scope fixed on top allows the player to zoom in on his or her target.

During Apprehension, a scientist refers to the crossbow as a "tranquilizer gun", while an HEV Suit audio clip (not heard in-game, but included in the game's files) identifies the crossbow's ammunition as "neurotoxin-treated crossbow ammunition". Its effects on Ichthyosaurs (which stop and twitch before losing consciousness upon being struck by several darts) support this. However it appears to be lethal to most other targets.

Apart from the scientist's comment, it is unclear as to whether this neurotoxin is really a non-lethal tranquilizer, but just at such a concentrated dosage to be fatal to human sized targets, or if it is in fact a lethal drug developed for use against Xen creatures by experimenters; nor is it clear whether the neurotoxin has an instantaneous effect or if it is the force of the impact that kills a target.

Because the Crossbow was used only for unique tasks at Black Mesa, such as knocking out Ichthyosaurs (due to its ability to fire under water), ammo for it is scarce, and neither soldiers nor security guards are ever seen using one. The only exception is one crossbow that is found in a specimen locker lying next to a dead security guard in the chapter Questionable Ethics.


  • The Crossbow is effective against most enemies, but is best saved for tough, slow moving enemies or those who are unaware. If attacking marines or Vortigaunts, aiming for the head results in a one hit kill, even on the hardest skill levels. In multiplayer, a zoomed shot to the head will instantly kill a fully healed and fully charged player.
  • The Crossbow is particularly effective against Ichthyosaurs, since it is both powerful and capable of firing underwater. However, when fired underwater the bolt may lift or lower based on if the player fires upwards or downwards. Firing upwards causes the bolt to fly lower than your aim, and firing downwards causes the bolt to fly higher than your aim. Firing straight ahead is unaffected.
  • Once targets start to move in any direction except a straight line, using a Crossbow becomes a game of chance. Aim in front of the opponent. If the opponent is using one, get into the habit of zigzagging and generally moving in awkward patterns.
  • Like the .357 Magnum Revolver, it can be very lethal at close range.
  • It is interesting to note that even though the Crossbow is said to kill targets because of its toxin, one shot can destroy a turret, which is metallic and inorganic, supposedly immune to arrows.
    • It is possible that the developers simply wanted it to function like a sniping weapon as a research facility won't have access to a sniper rifle because it lacks any clear purpose to be there.
  • This is the only weapon that can kill a HECU soldier without alerting nearby HECU soldiers.
  • It is possible to perform stealth kills with the crossbow due to it being "silent" when fired, despite the sound being present in-game.[2]

Behind the scenes

  • The female Black Ops were originally to be armed with crossbows. The quivers used to hold the crossbow bolts are still featured in the model, attached to the belt.
  • The earliest model has purple bolts instead of silver. This is so because the crossbow in the beta was supposed to use "Neurotoxin-treated" bolts. A unused H.E.V line also refers the crossbow ammunition as "Nuerotoxin-treated crossbow ammunition".
  • The last beta model lacks a scope. Also, it lacks the purple colored bolts, though it still used Nuerotoxin bolts. This explains that the concept of using Nuerotoxin bolts was cut very late in the development.
  • The retail crossbow has a unused idle animation. This said animation was also present with the beta models.


  • In multiplayer games of Half-Life, the Crossbow has a somewhat different functionality: When fired ordinarily, the bolts explode on impact with a small amount of splash damage. When fired while using the scope, the bolts do not explode, and travel to their target instantaneously, just like the Colt Python.
  • Crossbow bolts in Half-Life are not affected by gravity. However, in Half-Life: Source, the bolts are affected by gravity over long distances and follow a slight downward arc as they travel. Users firing over long distances must account for this drop by aiming slightly above the target.
  • Aside from the 9mm Glock and the RPG, the Crossbow is the only projectile weapon that can be used underwater.
  • During reloading the entire magazine is pulled through the gun but the bolt holder doesn't come out of the top and simply disappears.
  • There is one Crossbow magazine found in Power Up, even though the Crossbow is not obtainable until Apprehension.
  • Additional ammunition can be found in a hard-to-reach room just before the player obtains the Crossbow. There are four magazines in a submerged room of Apprehension in which Gordon must swim through the sewers to retrieve the magazines.
  • Despite the crossbow not being obtainable (without cheats) in Half-Life:Opposing Force, Crossbow ammo can be found in a Weapon Box in one of the reachable Xen locations using the Displacer Cannon, as weapon boxes are supposed to contain, well, all types of ammo.
  • Originally, there were supposed to be sounds for the removal and insertion of the magazine for the Crossbow.




List of appearances


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