Stalker



First Seen: Half-Life 2, Chapter Nine, Nova Prospekt
 * Health total: 25
 * Weapon damage: Welding Laser (estimated 2 per second, but is a sustained fire)
 * Entity:  (only functional in Episode One)

The product of extreme, brutal Combine engineering, stalkers are humans who have been experimented on by Combine scientists, had their higher brain functions severed, nano-devices embedded into their skin, and their bodies physically altered. Their limbs have been removed and replaced with mechanical extensions; most organs, excess fat, as well as muscle have also been removed and what appear to be metallic augmentations added to parts of their body. "Stalkers", the codename by which the Combine know them, appear to be in constant pain, as their loud wheezing indicates. A stalker can't talk, and instead can only make beastly roars, most likely because its vocal cords, or perhaps entire larynx, has been removed, as the metallic hole in their throats suggests. The lack of higher mental functions would also prevent them from forming any kind of coherent vocalizations.

For ease of maintenance and to bring a physical dependence on the Combine, the stalker's digestive tract has been removed, resulting in the stalkers surviving solely on a saline solution that the Combine provides. Stalkers would originally have to work to gain the metallic legs, proving they could be trusted with additional movement. All stalkers appear to come from male human beings, as they have facial hair stubble. However, this may simply be a developer oversight – even female citizens of City 17 will occasionally comment "They're never gonna make a stalker out of me!"

Humans are turned into stalkers at Nova Prospekt, and are then transported to the Citadel to do slave labour for the Combine. They are transported by Razor Trains, and are confined in pods during the transportation. Despite being seen in Nova Prospekt and the Citadel, stalkers are never actually engaged in combat during Half-Life 2. However, it is possible to see and battle against them in Half-Life 2 modifications such as Garry's Mod, and it is necessary to engage in combat with them in order to achieve mission objectives in Half-Life 2: Episode One, as their lasers prevent certain tasks from being completed. Episode One is also where the exact nature of stalkers is first revealed. In Episode One, the player and Alyx enter the Citadel. After a bit of progress, the player and Alyx enter a room with two stalkers working a forcefield, temporarily preventing progress. Alyx states that the stalkers "shouldn't bother us if we leave them alone". Interestingly enough, when the player is in the core of the Citadel and kills one of the two stalkers, the remaining one will turn to face the player and roar at him. The stalker will then proceed to attack the player with the laser tool.

It appears that the citizens of City 17 have a full knowledge and understanding about stalkers, what they are, and how and where they are "made." Alyx Vance comments on Nova Prospekt: "It used to be a high-security prison, it's something... much worse than that now." Barney Calhoun also makes the comment, "He was about to board the express to Nova Prospekt!" at the start of the game. All comments indicate that the citizens know about stalkers, as well as Nova Prospekt.

Stalkers, when spawned using the console in Half-Life 2, shoot lasers from beneath their feet at the player, treating the player like an enemy. This is unfinished code originally intended to be in Half-Life 2 - the laser was originally supposed to be fired from the tools attached to the stalker’s head. If the player kills a stalker the game will crash, as the model does not have a "ragdoll" state. Some mods have successfully avoided this problem (Gmod, for example). In Episode One, they now possess ragdoll physics and the lasers shoot from the head as originally intended.