The Boiler is a caste of Xenomorph that was encountered by Colonial Marines from the USS Sephora on LV-426. It possesses a unique form of attack, whereby it will forgo the typical melee or spitting attacks used by other Xenomorphs in favour of suicidally rupturing its own body, drenching nearby targets in huge quantities of acidic blood.
The Boiler first appeared in Aliens: Colonial Marines and was one of several new Xenomorph castes created for the game.
Though the Boiler resembles an ordinary Xenomorph Warrior, its body is horribly deformed, covered with boil-like pustules and lesions and being generally decrepit in appearance. Their exterior armor is excessively aged and fragile, leaving them quite vulnerable to attack, while the numerous deformities on their bodies restrict the Boiler's movement to an awkward upright hobble. Most notably, they apparently lack the ability to "see" like other Xenomorphs and are essentially blind, reacting instead to noise and vibrations in their environment. They spend much of their time crouched and immobile, resembling fossilized husks, but will awaken upon detecting nearby sounds and begin to search for the source. When Boilers move about, the pustules on their body tend to glow, although this glow diminishes when the creatures are at rest.
Boilers adopt a kamikaze attack strategy whereby they charge their enemies before causing themselves to self-destruct, suicidally exploding and showering their enemies in acid. It is not clear how such behaviour may have evolved, although it likely emerged as a result of their weak armour and extensive deformities, which would otherwise render them nearly useless in combat. While a single Boiler is rarely a threat to a well armed and prepared team, a swarm can overwhelm entire groups in no time at all, especially given how their suicidal attack can cover a significant radius.
Possible role in Xenomorph hierarchyEdit
While it is unknown exactly what role the Boiler fulfils in Xenomorph society, their appearance, generally sluggish nature and blindness could be interpreted as a result of advanced age; it is possible they are elderly Xenomorphs near the end of their natural lives. The fact that many of the Boiler husks encountered in the sewers of Hadley's Hope do not revive even when loud noises occur nearby seems to imply that these individuals have in fact died of natural causes before being encountered. They may be the last remaining Xenomorphs from Aliens, having survived the explosion of the Atmosphere Processor and subsequently reached the end of their natural life cycle. If this is the case then they would be the first instance of Xenomorphs naturally expiring due to old age.
The Boiler can be acquired in multiplayer by awakening it in select locations after a certain amount of time has passed in a game. They cannot climb walls and they have very limited radar sight. However, they are extremely fast and have a very deadly suicide attack that can be triggered by holding down the attack button. Boilers will also explode if sufficiently damaged, and have an added ability to spit acid not seen in singleplayer, although its range is limited.
- Assuming the ageing theory is true, the Boiler is similar to the Carrier Form of the infectious alien species in Halo known as the Flood. Both Boilers and Carrier Forms are evolved from combat castes that have become too damaged or useless to fight, and have changed to become volatile and explosive.
- One explanation often suggested by fans for the Boilers' creation is that they are some kind of mutation created by radiation from the Atmosphere Processor explosion. However, the chances of radiation creating an entire group of identically-mutated creatures are virtually nil. Moreover, the game takes place only 17 weeks after the explosion, and at no point during the story is it suggested there is any abnormal or excessive radioactive activity at the colony. Given the fact that the Xenomorph are an alien species with a very accelerated metabolism unlike anything found on Earth, the possibility still exists, though, that the mutation took place as a response of these organisms' biology to the Atmosphere Processor's explosion.