The Bloodburster is the infant form of the Neomorph species and the third stage of its life cycle. It is most well known for its horrific method of gestation — it is implanted into a host via microscopic motes, dispersed from egg sacks, that invade the host's body through open orifices. The host's health rapidly deteriorates during gestation, ultimately culminating in the Bloodburster violently puncturing the skin and clawing its way to freedom.
While a Bloodburster is the infant form of a Neomorph, it is "born" almost fully formed, similar to the Deacon from Prometheus. The birthing process is also similar to the Xenomorph Chestburster, although the exact point of emergence varies depending on how the host was infected.
The Bloodburster is a small quadruped that is capable of defending itself, unlike the Chestburster, and resembles an infant Runner. It also has pale, white-grey skin with a somewhat translucent appearance, attributes that resemble those of a Hammerpede.
The Bloodburster will take on traits of the host, just like the Xenomorph. However, it will also take on certain characteristics depending on how it emerges. When a Bloodburster bursts out of Ledward's spine, it possesses dorsal fins on its back. However, when a Bloodburster emerges from Hallet's mouth, it does not display these features, although its skin is more translucent and has a shine to it.
Notably, Bloodbursters are aggressive from the moment of birth, as shown when a Bloodburster born from Ledward immediately attacked and killed Karine mere seconds after it hatched. This is unlike regular Xenomorph Chestbursters, which generally attempt to flee to an area of safety after birth.
- Before its official name was given, the infant Neomorph was referred to by fans as a "backburster".
- The Bloodburster has a notable appearance, similar to the Runner. According to Ridley Scott, this was a purposeful design choice when creating the Neomorph.