Hover Turret

The Hover Turret (also referred to as the Lazer Turret) is an unused turret from Portal 2. While the turret's programming is still in place within the game's files, it lacks a model; spawning it with a code or placing it with a level editor will result in a blue "ERROR" placeholder model appearing instead. In a pre-release screenshot, it was shown to use the model of the cores from the first game, switching between them depending on its state: it used the Curiosity Core's model when firing at the player, the Anger Core's model when on the ground, the Intelligence Core when scanning, and the Morality Core's model when facing away from the player. Despite its name, the turret does not actually hover, but is suspended by a cable from the ceiling. The eyes of the turrets firing at the player were a slightly different shade and glowed more than the Curiosity Core's.

It can be spawned in-game using the cheat command ent_create npc_hover_turret, and can also be placed through Hammer.

Functionality

The Hover Turret hangs from a rope attached to the ceiling, and if configured to do so in Hammer, slowly rotates while idle. Like the standard Sentry Turret, the Hover Turret is initially inactive until a player enters its field of view. The turret fires a blue-colored laser that hurts (and eventually kills) any player that it touches in a manner similar to a Thermal Discouragement Beam. Unlike a Thermal Discouragement Beam however, the Hover Turret's laser does not inhibit movement and cannot be used to activate Thermal Discouragement Beam receptacles.

Once the Hover Turret has spotted a player, it will rotate to follow them.

The Hover Turret breaks off its tether if the player picks it up while close enough or it is hit by an object. If picked up, it can be carried and will not fire its laser until placed gently on the floor, when it will then resume firing upon the player. If dropped from above the player's height (about 128-192 Hammer units), it will explode after a brief countdown.

Trivia

The Hover Turret supposedly has code to allow it to actually fly, but it is unknown if there is any way to activate this in the final game.
Like other NPCs, the Hover Turret has a sound script file in the portal2\scripts\ folder; however, none of the corresponding audio files that it references were shipped with the retail game.^[1]
While the original model is missing from the files, a fan-made patch can be downloaded that restores most of the NPC's functionality.^[2]
The Hover Turret's tether is a unique entity known as ent_hover_turret_tether, it is generated automatically if the hover turret has an attachment target set in Hammer.
The Hover Turret produces glass futbol chunks when exploding.
A trio of Hover Turrets appear in the intro for the CoreHub beta of Portal 2, they can be seen having the following exchange: "Hey, what's going on over there?" "I didn't see anything!" "Why am I not surprised?"