The Chestburster, designated a "Stage 2" Xenomorph by Weyland-Yutani scientists, is the infant form of the species Xenomorph XX121 and the third stage in its life cycle. It is most well known for its horrific method of gestation — it is implanted into a host lifeform's chest cavity by a Facehugger, and upon maturing it will erupt violently from the host's chest, killing them in an incredibly bloody and traumatic fashion. Chestbursters are small, generally not more than a foot tall and around two feet long including their tails, although larger examples have been seen.