Displacer Cannon

The Displacer, also known as the XV11382, is a type of extremely compact and portable teleportation machine that was developed at the Black Mesa Research Facility. The displacer could also be used as a weapon, the Displacer Cannon. A displacer 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 displacer and the device’s user.

Overview
The portals generated by displacers 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 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 ionise the air and can result in a form lightning to arc between the portal and objects that it passes, a hazard that displacer operators must be conscious of. When the portal comes into contact with a significant amount of mass, it will lose enough energy to destabilise 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 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’s self-teleport feature, and so safety precautions must still be taken.

The dangerous aspects of displacer technology also allow it to be used as a powerful weapon, and for this reason the device is sometimes known as the Displacer Cannon. 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. Additionally the teleportation destination can be set to send anything it hits to an undesirable or dangerous location.

Corporal Adrian Shephard, a member of the Hazardous Environment Combat Unit sent into Black Mesa, found a displacer after being teleported to the Xen border world. 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 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 was 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 the died was too rushed to operate it properly.

The compact teleportation technology of the displacer appears to have been lost, since the teleporters built recently by the Resistance against the Combine are far larger than displacers, but it is possible that portable teleporters may eventually be developed once again. The Aperture Science Handheld Portal Device is a good example of this.

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

In the fan-made PC port of Half-Life: Decay, the displacer can be found in level 5, Domestic Violence. 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 displacers. 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, but no more ammunition can be found for the rest of the game.

List of teleport locations
There were several notable locations that the Displacer sent Shephard during the game, including:


 * The Training Course, populated with Vortigaunts that attack the Holographic Instructor in vain.
 * One of the locations Gordon Freeman was teleported to briefly during the start of the Resonance Cascade (the one with non-hostile Bullsquids). This is also where the Half-Life: Decay bonus chapter Xen Attacks starts. This location can be seen at least three times.
 * A cavern full of water with a scientist corpse at the bottom and what may be Gina Cross's corpse (the female HEV Suit scientist model, gina.mdl).
 * In the room with the one-man teleporter Shepard can be teleported high above a Xen location and fall to his death. This results in a message similer to the one if he uses Gordons portal. The message reads "Accidental death. Displacer self-teleport mishap."

List of appearances

 * Half-Life: Opposing Force
 * Half-Life: Decay