From D&D Wiki
The xenomorph(Internecivus raptus), or 'Alien' as it is widely known, is a parasitic extraterrestrial creature created by an ancient planar or space-faring race as a bio-mechanical weapon. They possess an endoskeleton and black exoskeleton and powerful acid for blood. The species exists as an ant hive structure. All xenomorphs answer to a queen. She reproduces in an oviparous manner, leaving behind a leathery egg with a parasitic Facehugger inside. The Facehugger finds a host and deposits its embryo into the host and dies. The incubation period lasts 1d12+4 hours for a normal xenomorph, and 1d4 weeks for a queen. At the end of the gestation cycle, the embryo (now a Chestburster escapes the host via its namesake.
A xenomorph possesses the following traits (unless otherwise noted in a creature’s entry).
- Hivemind (Su): All xenomorphs within 500 feet are in constant psychic contact. If one is aware of a particular danger, they all are. If one in the group is not flat-footed, none of them are. No xenomorph within range is considered flanked unless all are.
- Acid Blood (Ex): If a xenomorph is struck by a melee weapon, it sprays powerful acid blood from the wound. The wielder of the melee weapon must make a Reflex save (DC 10 + 1/2 xenomorph's HD + Con modifier) or the weapon dissolves immediately and its wielder takes acid damage. If the weapon is an unarmed melee attack or natural melee weapon, the wielder instead takes acid damage. This blood deals acid damage equal to the Reflex DC per round upon contact with any objects, and all xenomorphs are immune to its effects. The save DC is Constitution-based.
- Frightful Presence (Ex): The appearance and ferocity of a xenomorph is deeply unsettling to its enemies and prey. This ability only affects creatures with fewer HD than the xenomorph. An affected creature may resist with a successful Will save (DC 10 + 1/2 xenomorph's HD + Cha modifier) or be shaken for 5d6 rounds. This ability has a range of 30 feet.