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The Displacer Cannon is a portable teleportation weapon developed by Black Mesa before the Black Mesa Incident. A Displacer Cannon has two different modes: the first generates a displacement field (or portal) ahead of the user, allowing the teleportation of a single object or being. The alternate mode generates a portal behind the emitters, teleporting the user with the weapon and giving a significant amount of damage to anyone nearby right before the teleportation occurs.


The portals generated by Displacer Cannons were somewhat unique compared to other teleportation technology, as they did not have to be maintained by a constant supply of displacement energy; instead the displacement field was given a large amount of energy in a concentrated burst, allowing the portal to remain open for some time before the portal’s energy was depleted. To generate this degree of energy within such a compact device required a Xen crystal or some other imitation with exotic matter properties. The other key component was a nuclear mini-reactor fueled by Uranium-235, also used in the Tau Cannon and Gluon Gun weapons that were developed at Black Mesa.

A moving Displacer Cannon portal will travel in a straight line in defiance of gravity, teleporting the air and dust particles that it passes through, as they do not significantly deplete the displacement energy. This process will ionize the air and can result in a form of lightning arcing between the portal and objects that it passes, a hazard that Displacer Cannon operators must be conscious of. When the portal comes into contact with a significant amount of mass, it will lose enough energy to destabilize and collapse. In the brief moment before this occurs the matter in contact with the portal will be teleported, unless its mass exceeds the limits of the displacement field. This limit tends to be slightly greater than the mass of a human being; larger creatures (bosses), vehicles, dense objects or walls cannot be transported.

When the portal collapses it causes a displacement shockwave, a wave of extremely dangerous space-time distortions, anomalies and exotic particles that will damage the structure of matter. When a Displacer Cannon is used as a tool to teleport objects or beings, care must be taken that there is no one near that could be harmed by the shockwave, or objects that could sustain damage. A shockwave is also left in the wake of the Displacer Cannon’s self-teleport feature, and so safety precautions must still be taken.

The dangerous aspects of Displacer Cannon technology also allow it to be used as a powerful weapon. The user can purposely fire a portal near to an enemy or into the midst of a group of enemies; firstly the arcs of lightning may cause some harm, and then when the portal collapses after hitting the ground or wall the shockwave is capable of eliminating several human-sized targets. Finally, whatever that touches the portal is warped away to a presumably set destination, never to be seen again. The device can fire underwater, making it easier to defeat the Ichthyosaur if the player can time it right, as the Ichthyosaur moves around a lot and might cause the attack to miss.

Corporal Adrian Shephard, a member of the Hazardous Environment Combat Unit sent into Black Mesa, found a Displacer Cannon after being teleported to the Xen border world in the Opposing Force chapter "We Are Not Alone". The device appeared high in the air, along with the scientist who activated it, presumably in an attempt to escape from some threat. The scientist was killed by the fall but Adrian was able to retrieve the device and use it as a weapon. After teleporting enemies, Adrian never encountered those individuals again, and when he activated the device’s self-teleport feature he was sent to a different random location each time, usually in the Xen border world. It is possible that the prototype Displacer Cannon had no means of choosing a destination, or that the destination was supposed to be pre-set by some external method, and this was disrupted by the dimensional rift at Black Mesa. Since Shephard is a soldier rather than a scientist trained in teleportation technology it is also possible that there was some kind of control mechanism that he simply did not have the skill to operate, and the scientist that died was too rushed to operate it properly.

The compact teleportation technology of the Displacer Cannon appears to have been lost, since the teleporters built recently by the Resistance against the Combine are far larger than Displacer Cannons, but the possibility of their resurgence cannot be excluded. The Aperture Science Handheld Portal Device is a good example of this, as it persisted presumably before and after the Combine Invasion.

It should be noted that although the existence of this weapon was never announced, charts and blueprints of it can be seen in the offices the chapter Friendly Fire.

List of teleport locations[]

Using the Displacer Cannon always sends Shephard in a small location set in the current map. That area always features one or two portals bringing him back where he came from, so that he can resume his journey. These areas often feature dead Black Mesa scientists (lab coat and HEV Suit versions) and supplies, and non-hostile NPCs.

  • We Are Not Alone (of3a2): Set on Xen, this is the map where the Displacer Cannon is found. After witnessing Gordon Freeman teleporting to Xen, Shephard uses another portal, sending him to another Xen location featuring a Race X portal powered by a large Xen crystal from which Sprites fly and enter back to another portal located above, and a dead Survey Team member. There he witnesses a scientist teleporting high above, falling to his death on an island with a Displacer Cannon. Upon acquiring the weapon, Shephard can use it to teleport into a segment of the Training Facility, where he witnesses Vortigaunts attacking the Holographic Instructor without any effect. As Shephard is already on Xen when using the Displacer Cannon teleportation feature, it is the only teleport location not set on Xen.
  • Crush Depth (of3a4): From the Biodome Complex, Shephard can teleport himself to the same Xen location seen during the Resonance Cascade in Half-Life, and where the Decay bonus chapter Xen Attacks starts. There the Bullsquids drinking in the Healing Pool are still non-hostile. The portal teleporting back to Black Mesa is located behind Shephard after teleporting, in a cave.
  • Crush Depth (of3a5): Again from the Biodome Complex, it teleports to a Xen location where a scientist who came there with another Displacer Cannon is hanging from the cliff of an island. However Shephard does not teleport on solid ground, and falls to his death in the void. The end message then reads: "Status: Accidental death - Postmortem: Displacer Cannon self-teleport mishap". One of the islands features a cosmetic Healing Pool.
  • Crush Depth (of3a6): Again from the Biodome Complex, it teleports to a Xen location where corpses of Survey Team members are found. A portal leads back to the Biodome Complex. It will sometimes lead to a Biodome Complex area featuring another portal teleporting back to another spot of the Xen area, then teleporting back again to the Biodome Complex.
  • Vicarious Reality (of4a1): Again from the Biodome Complex, it teleports to a Xen cavern where a scientist, thankful to be rescued, is found. The scientist can then teleport through the portal, but he cannot be seen after following him. There can also be found a Healing Pool, several Light Stalks and Xen crystals.
  • Vicarious Reality (of4a2): Again from the Biodome Complex, it teleports to a Xen area with three islands linked together vertically by a column, Xen crystals, Survey Team member corpses and two flocks of Boids.
  • Vicarious Reality (of4a3): Again from the Biodome Complex, it teleports to the same Xen area as the one visited in of3a6, only that the skybox is plain black. It is briefly seen, with no dead Survey Team members and no supplies, in the Blue Shift chapter Deliverance.
  • Pit Worm's Nest (of4a4): From Waste Processing Area 3, it teleports to a large flooded Xen cavern with Light Stalks, the corpse of a lab coat scientist and of Gina Cross[2] (using the multiplayer model "gina.mdl"). Despite being set on Xen, the Pit Worm can still erroneously be heard from that area.
  • Pit Worm's Nest (of4a5): Again from Waste Processing Area 3, it teleports to the same fatal Xen area as the one that can be reached in of3a5, which would involve Shephard falling to his death.
  • Foxtrot Uniform (of5a1): From Sector G's hangar areas, it teleports to the same Xen area as the one visited in of4a1, only that there is no scientist.
  • Foxtrot Uniform (of5a2): Again from Sector G's hangar areas, it teleports to the same Xen area as the one visited in of3a4.
  • Foxtrot Uniform (of5a3): Again from Sector G's hangar areas, it teleports to the same Xen area as the one visited in of4a3.
  • Foxtrot Uniform (of5a4): From Sector G's Hydro-Electric Dam, it teleports to the same Xen area as the one visited in of4a4, except that it now features two portals. One portal teleports back to the hangars side of the dam, the other to the Advanced Biological Research Lab side.
  • "The Package" (of6a1): From the desert area located after the Hydro-Electric Dam, it teleports to the same Xen area as the one visited in of4a1. The scientist is again there, but does not teleport when walking through the portal.
  • "The Package" (of6a3): From Sector E's larger Ordinance Storage Facility, it teleports to the same Xen area as the one visited in of4a4. Both portals teleport back to the same spot, which changes depending on what spot Shephard is before teleporting.
  • "The Package" (of6a4): From the underground parking lot of Sector E's larger Ordinance Storage Facility, it teleports to the same Xen area as the one visited in of3a4.
  • Worlds Collide (of6a4b): From under the underground parking lot of Sector E's larger Ordinance Storage Facility, it teleports to the same Xen area as the one visited in of3a4.
  • Worlds Collide (of6a5): From the Gene Worm area of Sector E's larger Ordinance Storage Facility, it teleports to a Xen area featuring three islands, a dead Survey Team member and his Weapon Box, and a few Xen crystals.



  • In the fan-made PC port of Half-Life: Decay, the Displacer Cannon can be found in the chapter Domestic Violence, in a newly created room of the Level 3 Dormitories. In order to obtain it, the player(s) must find three parts of the secret code on the level, then find a big PS2 controller and "shoot" the code. A previously closed door to one of the rooms will slide open, revealing two Displacer Cannons. They can be used to teleport to a secret level, once again available only in the PC port. There, another secret code can be found. Entering this code back in the dorms will result in the unlocking of the alien mission. After this teleportation, some ammo will be left in the Displacer Cannon, but no more ammunition can be found for the rest of the game. Furthermore, the first-person model still uses the soldier hands from Opposing Force as opposed to the HEV suit hands.
  • The Displacer Cannon's official name may be a reference to George Lucas' THX-1138, which is referenced many times throughout the Star Wars saga, and other works.
  • In a Half-Life: Opposing Force new game, the player can obtain the Displacer Cannon with the impulse 101 cheat earlier than the player is supposed to receive it in the We Are Not Alone chapter. However, if the player uses the cheat and alt-fires the Displacer Cannon, it won't teleport them.
  • In the view model of Displacer Cannon, the player can barely see the white letters BLACK MESA XV11382 written on the thick black cable in the bottom-right side of the screen.
  • Self-teleportation uses 60 ammo and it cannot be refilled in Xen. This is to prevent player using the teleportation while in Xen.
    • If the player uses console cheats to get ammo while in Xen, they will be re-teleported to the same Xen area.
  • Cave Johnson's quote in Portal 2 saying "You most likely used one of the many products we invented... But that other people have somehow managed to steal from us... Black Mesa can eat my bankrupt-" (interrupted by Caroline) suggests that the Displacer Cannon (and other portals) was a "rip-off" of the Quantum Tunneling Device and the Handheld Portal Device.
  • The overall design of the Displacer Cannon and its primary fire bears a resemblance to the BFG from the Doom series.
  • In a deleted scene from We Are Not Alone, Otis and a scientist are studying the Displacer Cannon.
  • It uses Uranium-235 as ammunition despite the HUD showing a bullet icon (patched as of Oct 2019).
  • During the scene of the scientist with the first Displacer Cannon you find falling to his "death" by being at the exact place the scientist would have landed before he lands with the god mode cheat enabled and waiting till he lands on you, the scientist will survive, but he will seem to be floating indefinitely with his falling animation never ending while not landing at all.


List of appearances[]