Acid Blood. When the Xenomorph takes damage of any type but psychic, each creature within 5ft of the Xenomorph must make a DC 15 Dexterity saving throw. On a failed save a creature takes 2d6 acid damage or half as much damage on a successful save.

Immutable Form. The Xenomorph is immune to any spell or magical effect that would alter its form.

Out of the Shadows. The Xenomorph has advantage on its initiative rolls.

Multiattack. The Xenomorph makes two claw attacks, one bite attack and one tail attack. Alternatively the Xenomorph attempts to grapple the target instead of making its claw attacks. If successful the Xenomorph can make one headbite attack as a bonus action.

Claw. Melee Weapon Attack. +9 to hit; 5ft reach, one target. Hit: 1d6+6 slashing damage.

Bite. Melee Weapon Attack. +9 to hit; 5ft reach, one target. Hit: 1d10+6 piercing damage.

Tail. Melee Weapon Attack. +9 to hit; 10ft reach, one target. Hit: 1d8+6 piercing damage.

Headbite. Melee Weapon Attack. +9 to hit; 5ft reach, one grappled target. Hit 2d12+6 piercing damage. If the target is reduced to 0 hit points in this way it dies instantly as its brain is destroyed.

Prowling Nightmare. The Xenomorph can use the Dash, Disengage or Hide action as a bonus action.