The Lurker is a caste of Xenomorph very similar to the Drone. Lurkers are easily identified by their usually smooth head carapaces. Unlike the far more common Warrior caste which tend to employ direct assaults and swarm attacks, using sheer weight of numbers to overwhelm defences and subdue their prey, Lurkers prefer to keep their distance and lurk in the shadows, only attacking when the time is right.
Lurkers tend to walk on all fours most of the time, although they have been known to stand on two legs when fleeing or attacking with their claws. Lurkers are dark in color, typically black but can switch to one of five new tones (Aureus, Inquinans, Caeruleus, Aeruginosus, Porhyreus). Their most distinguishing features are their smooth heads (although some Lurkers have a hole in the middle of their domes, exposing the spikes underneath) which can mutate into one of three new domes, the Cornigus, the Cristatus and the Cataphractus. Some Lurkers also have what resembles a human skull underneath their domes, similar to the Drone. Lurkers also have thinner dorsal tubes than most Xenomorph castes, three fingers, green tinted shoulders and feet identical to that of a Warrior. Lurkers use their agility to outsmart prey. This form of attack requires a thin, spindly figure, which makes it trade brute force for overwhelming speed. Lurkers also have a stronger exoskeleton than Warriors giving them the ability to take more damage.
The Lurker Xenomorph is regarded by some as the perfect hybrid between a Warrior and a Runner. It almost has the same speed and prowess as a Runner does, mixed with the strength of a Warrior, which allows it to easily knock down Marine opponents.
When attacking, Lurkers primarily employ ambush tactics, and are almost never seen working in coordination with other Xenomorphs, preferring instead to operate alone. They are shown to be intelligent and patient, employing stealth in their assaults, often seeking to blend in with their environment and waiting for their prey to come within range before striking. The Lurker's primary attack is to pounce on their prey and attempt to stab them with their tail or attack them with their claws. Lurkers are also able to leap great distances. Lurkers have been known to create holes in the walls of a Hive next to a Chestburster host. Lurkers will then hide in the hole and blend in with the rest of the Hive and when a enemy gets to close to them the Lurker will emerge from the wall and attack. Lurkers seem to be more intelligent than the Warrior caste as they have been shown commanding them.
The name "Lurker" was coined for this Xenomorph due to the way it camouflages itself.
In Aliens: Colonial Marines multiplayer, the Lurker is a playable Xenomorph caste, used for speed and scouting enemy players. The player can use the unique pounce ability to pin down a Marine and kill them with three claw swipes. However, a fellow Marine can shoot the Lurker player off of the pinned ally, saving them.
- The Lurkers are often said to be Drones (due to their virtually identical appearance), but the official strategy guide makes it possible they are a separate caste.
- The Lurker's appearance is obviously inspired by the Alien (a Drone) seen in Alien.
- Lurkers also have a human skull under their dome, a trait the Alien also possessed. However, the skull is not visible in the final game as the Lurker's dome is completely black, despite the skull still being present on the model used in-game. A strain of Lurkers seen in the Origin Facility holding pens have this skull exposed as well as a spiked cranium, notably similar to the much larger Raven. Very interestingly, the Raven also makes the characteristic Lurker "snarl" on occasion - a noise that Warriors and Spitters are incapable of.
- The Lurker's tactic of hiding in the wall of a Hive next to a host is likely inspired by the similar tactic seen being used by Warriors during the Hive ambush in Aliens.
- A Lurker is the first Xenomorph encountered in Aliens: Colonial Marines (not counting the open and unopened Eggs or dead Facehuggers).
- The Lurker's reliance on stealth is visually reflected in their teeth, which are smaller and more fang-like than the soldier.
- Drone - A similar Xenomorph caste.