- "Move move! He's on the wall above - WHAT THE FUCK IS THAT!"
- —Alien Necromorph introduction
A Necromorph variant of the mysterious alien species once native to Tau Volantis, these menacing, strong beasts stand around 7 to 8 feet tall (a little over 2 meters tall) and are very similar to Brutes in overall size, appearance and behavior and are possibly the Brute variants made from the extinct natives. They have two appendages on the chest.
These Necromorphs have three main attacks: charging towards the players, giving a powerful punch if the player gets too close and being able to burst out Crawlers made from the extinct alien hosts. The Necromorph will burst out the Crawlers if the player gets too close but they can also burst them out if they are far away, possibly to cause chaos and distract the players while the Alien Necromorphs begins charging towards the player.
One notable characteristic of this Necromorph is the eerie, high-pitched whistling sound it produces while attacking; this sound is derived from the resonating chambers known to be possessed by its alien host.
- Stasis proves to be an effective tool when fighting them, as it allows Isaac to fire his weapon into the Necromorph at the right moment for optimum results. Even using high-accuracy such as the Javelin Gun could prove to be a difficult shot against the brute-like beasts.
- High damage weapons (such as a shotgun) can be extremely effective.
- Most Alien Necromorph encounters rarely end with a single fight, many times another will be encountered almost immediately or shortly afterwards, so be sure to fight conservatively with ammunition and stasis.
- Chainguns (telemetry spike + diffraction torus) with the stasis coating mod are very effective at stopping them. Acid bath is also very effective, as the additional damage over time will put them down before they have a chance to get into range.
- Using a gun modded with a ground diffractor will kill the Crawlers that it expels from its belly and will NOT set their bodies off. Use them against the behemoth to conserve ammo.
- Dismembering their legs will effectively reduce the chances of them charging at you.
- The blueprint-based weapon Seek And Destroy can also be useful when fighting the Alien Necromorphs. The explosions from the projectiles it fires can easily kill the Alien in two shots.
- The Contact Beam is also a good choice when it begins to rear. It usually takes two shots.
- If you have the explosive under barrel attachment for the rivet gun or javelin gun and hit the Alien necromorph and blow up the last shot with a acid bath attachment to help a bit if the explosion didn't kill it.
- Using the Magnesium Afterburner with a few Damage circuits can kill the Alien Necromorph in a matter of seconds.
- An effective killing strategy is a bit like the brute killing strategy, Stasis the beast and then shoot it in the back of its legs and arms.
- Another effective strategy is to have an upgraded Seeker Rifle with Stasis Coating attachement. If the weapon has full damage and a slightly better than stock rate of fire, it will kill the creature in a handful of shots, long before it reaches you.
- If Isaac or Carver has low health, they will simpy fall over and possibly get ripped to pieces if they get hit by the Necromorph's many attacks.
- The Necromorph MAY not have any special death animations, but it is possible as the Exploder got new animations as well.
- It is possible the Alien Necromorphs are a variant of the Brute, just created from the different body-structure of the extinct alien race. Because the aliens were so huge, there was no need for multiple bodies to compose the entire Necromorph, unlike with the human variant. The both Necromorphs share similar body structure, size as well as their attacks. They also both can burst out "bombs" made from Necromorph bio-mass, except the alien variants are able to spawn infant aliens as opposed to the human variant that bursts out explosive sacks only when the creature has received major and critical damage by losing one of its arms.
- Unlike all previously-encountered Necromorph strains, the mutations to the Alien's bodies appear minimal at best, virtually non-existent, with only red mutated patches appearing in select areas on their bodies, they are otherwise indistinguishable from the uninfected remains of the aliens found under Tau Volantis's surface.
- Unlike the Brutes of previous games, shooting an Alien anywhere on its body will cause damage to it, likely because it lacks the former's armored plates, however it also becomes nigh-impossible to halt a charging Alien unless the shot tears off a limb or two, or outright killing the creature.
- The Alien Necromorphs can be decapitated, though like most previously-encountered strains of Necromorphs, it will not hinder the creature in any way aside from moderately damaging it.
- When killed, they drop three items rather than the normal one, and do not require manual looting (stomping or otherwise attacking the corpse).
- Despite their corpses being easily movable by simply walking into them, they are too heavy to be picked up by kinesis, attempts to do so will only slightly budge them.
- The type of Crawler it drops is made from some kind of alien creature rather than human infants.
- This is one of the few Necromorphs susceptible to shots to the center of the body, i.e. is effectively taken down without dismemberment.
- During the initial expedition to Tau Volantis, several Alien Necromorphs were discovered frozen within the planet's surface. Upon thawing, these thought to be dead creatures returned to life, slaughtering members of the science team. This further adds to the Necromorph's already impressive physiology, able to survive millions of years encased in ice.
- The Alien Necromorphs will retreat when the player stands on the launch pads located in the Alien Machine (allowing travel to the various sections of it). Simply running on and off the platform will make them turn around and run a bit. This behaviour is similar to that of the Brute around stairs.
- Towards the end of the game is a good time to get the Close Encounter achievement, as long as you kill the ones you find.
- It is possible the Alien Necromorphs were first female aliens of the extinct species as they contain a huge amount of Crawlers that appear to be infants of the aliens. The physiology of the species could have been similar to a fish that can store thousands of eggs inside its body.