Stalker

The Stalker is a category of machine in Horizon Zero Dawn. A medium-sized Combat Class machine, the Stalker employs stealth rather than open aggression, being able to turn invisible and deploy proximity mines.

History
Unlike the Zero Dawn terraforming machines, which were designed and controlled by Zero Dawn’s governing AI GAIA, the Stalker was designed by the AI HEPHAESTUS, which had previously manufactured the machines under GAIA’s direction. When GAIA self-destructed, HEPHAESTUS became hostile toward humans for their predations on the terraforming machines for parts and resources. Thus began the phenomenon that the tribe’s called the Derangement. In an escalation of the phenomenon, HEPHAESTUS then began producing combat machines, including Stalkers; it apparently created Stalkers from an unknown pre-Derangement Stalker-like machine.

Appearance
The chassis of a Stalker faintly resembles that of a chameleon or a rat, while also being distinct from that of the other known combat machines in two respects. Firstly, whereas these machines are heavyset and built for power, Stalkers are slender and streamlined. Secondly, whereas the armour of these machines consists of large, white fitted pieces, a Stalker's armour plating is black, and is composed of relatively small hexagonal plates that fit together in a chainmail pattern. Four optical sensor arrays are located on each side of their head, with the sensors arranged in a trapezoidal configuration. Each of their four feet is equipped with three claws. A dart gun is located between its shoulders. On each hip is a mine launcher that drops proximity mines. A power cell is atop its lower back, to which four long, antenna-like structures are attached. The machine has a retractable tail that is almost twice as long as its body, equipped with a sharp spike at the tip. Finally, a camouflaging device called a Stealth Generator is mounted on the left shoulder.

Behaviour
Stalkers can be found on their own or in small packs. Built specifically for ambush attacks, the majority of them are deployed in The Jewel, where the dense foliage limits their visibility to humans. They usually position themselves cloaked with heads downward on vertical surfaces such as trees and cliffsides, in absolute stillness. Alternatively, they also walk about uncloaked, partially obscured by the jungle’s undergrowth. In either case, they frequently set alarms on the ground that loudly sound off and release flares in response to movement within a certain radius. These alarms are not triggered by anything smaller than a human, or by other machines. Upon the triggering of an alarm, they immediately converge on the alarm’s location to investigate.

Abilities
A Stalker’s adeptness at stealth and ambush make it lethal to anyone unfamiliar with its abilities. Foremost among these abilities is its cloaking ability. A Stalker’s stealth generator cloaks the Stalker from plain sight when engaged by bending light around its chassis. In the case of Focus users such as Aloy, it also cloaks the machine from scans. However the cloak is imperfect; through the Stalker cannot be seen, the cloak produces a shimmering refractory effect in the shape of the Stalker’s chassis that is visible to sharp eyes; this is the shimmer that Ghalidid saw. Additionally, it does not cloak the Stalker’s optical sensors, nor mask the distinct whooshing sound of it’s servomotors.

The Stalker’s most lethal weapon is its dart gun, which can kill a human with one shot. Even though the Stalker must momentarily de-cloak to use it, an unsuspecting human never sees the shot coming, since the Stalker fires it from long range. At closer ranges, a Stalker deploys proximity mines that damage and distract an enemy. Unlike the dart gun, a Stalker can deploy these mines while cloaked. It drops these mines as it swiftly changes its position, its cloak preventing it from being tracked. Additionally, though built for stealth and ambush, Stalkers are capable of formidable melee attacks, slashing with their claws and employing a swift bludgeon attack with their tails.