Neomorphs are a subspecies of Xenomorph encountered by the USCSS Covenant. There are many noticeable differences between the two species for example Neomorphs are far more animal like and almost always feed on their prey after they kill it unlike Xenomorphs. The Neomorphs animal-like nature could suggest a lower intelligence. Neomorphs like the Deacon also lack a inner mouth.
Neomorph's enter their host's body through spores, normally through the ear or nose, and gestate inside the hosts blood. These spores are released by a fungal pod growing on "Paradise" that have been altered by the black pathogen. Unlike Xenomorphs they can erupt from various parts of the body and have been observed to do so after a matter of hours since first implantation. The emerged creature is known as a Bloodburster before quickly growing and becoming an adult Neomorph.
The first Neomorph spore enters Ledwards ear and he rapidly becomes sick. Ledward is brought back to the landing ship when the first Neomorph emerges from his back and kills Karine before chasing Maggie who accidentally kills herself by shooting an explosive, however the Neomorph gets away.
The second Neomorph emerges from Hallets throat and escapes into the night.
The first Neomorph then returns, now a subadult, and attacks the surviving crew violently, biting Walter's hand off and tearing Ankor's face apart with its tail before being fatally shot by Rosenthal. Hallet's Neomorph returns (now grown into a toddler) and leaps at Rosenthal mauling her arm until they are rescued by David, and it escapes back into the night. David leads the survivors into the destroyed city where the Neomorph follows, tracking and killing Rosenthal. Soon after David arrives and begins to try to communicate with the Neomorph. For reasons not entirely explained it does not attack David (possibly because it recognises that he's a synthetic) however Captain Oram kills the Neomorph by shooting it in the chest which greatly annoys David. This is the last time a Neomorph is seen.