Autogun

"You hear that Autogun going off out there? We normally run supplies out to the White Forest base, but a few days ago the Combine cut off access."

- Rebel

The Autogun is a stationary Combine turret seen only in the Half-Life 2: Episode Two chapter Under the Radar.

Overview
The Autogun is used to stem the flow of Zombies pouring out of City 17 as well as block Resistance supply runs to White Forest. It has three blue search beams that behave like Overwatch Snipers (including their obsession with killing birds), but fires a much more powerful weapon which could drain the player's full health in only a couple of hits. It can only be defeated by sneaking around behind it and dropping a grenade into its control systems.

The black box attached to the back of the Autogun sucks large amounts of air into the weapon when the panel is opened, which could indicate that the weapon is Plasma-based. This would explain why the zombies hit by the beam also catch fire as well as breaking in half. It could be also  using dark energy as many of Combine's  weapons.

The gun is much faster than a sniper, and hits even harder. The only way to survive is to crawl through a trench between the wrecked cars in front of it and climb up the side of the house. The house itself is heavily protected, as the player can see three soldiers patrolling outside the building, and some other guards in the cabin.

Tactics

 * The Autogun will not hold fire if a friendly unit is in the way of a target, and will kill unaware Combine Soldier's who wander into its field of fire.
 * The Combine Autogun will not target Combine Zombies, even if all other enemies have been killed. This may be due to an error in the Autogun's targeting system, which renders it unable to distinguish zombified combine units from living ones.

Behind the scenes

 * According to the commentary notes, the gun has three cannons instead of one so the player cannot feel safe when the machine is aiming at a zombie.

List of appearances

 * Half-Life 2: Episode Two