Deacon

The Deacon — also known as a Proto-Xenomorph — is a bipedal parasitoid alien. It bears many resemblances to the Xenomorph; however, it possesses more human-like teeth and has an erect bipedal posture. Its head shape is also unlike that of Xenomorphs, and it seems to emerge from its host using its pointed skull as opposed to simply biting or punching through the ribcage.

It should be noted that the Deacon is not the same species of Xenomorph encountered on LV-426; but rather a more primordial variant. LV-223 was the location of a facility housing prototypes of the black goo that would later bring life to this primitive form of Xenomorph.

Appearance
The Deacon's anatomy has many similar features to the Xenomorph, but is very distinct in comparison. Like the Xenomorphs it is bipedal with an elongated skull, but it lacks a tail and has no mouth-like tongue. Instead, it has a more primitive jaw mechanism akin to a goblin shark. Its skin resembles that of the Xenomorph with an insectoid or reptilian appearance, although the Deacon has a distinct blue tone whereas the others have a significantly darker tone with very little color.

Life Cycle
A Deacon is implanted inside a host by a Trilobite. The Trilobite seen in the movie gestated as a fetus within Elizabeth Shaw's womb, where it grew with frightening speed. It was removed via cesarean before it had fully grown and developed, yet it survived this procedure after Shaw leaves the area. She returns to see that although she removed the creature from her body, it has grown immensely in size. The creature may be one of a kind since the Trilobite was a mutation.

The Trilobite has multiple tentacle-like appendages and skin that resembles that of a Facehugger. The Trilobite soon injects the Engineer with a tube-like organ that injects an egg/fetus through the Engineer's mouth. This behavior is similar to that of a Facehugger. It even dies after injection also like a Facehugger, indicating that the two are very likely related, though it has not been confirmed that this is so. The Deacon embryo is orally injected by the Trilobite and, after a short while, the Deacon is born. It bursts from the Engineer from his chest and abdomen, using its head to puncture and force its way out of the Engineer's body. This contrasts greatly to the Xenomorph birth which bursts out the chest as a larvae and later goes through metamorphosis to become an adult, whereas the Deacon appears to come out almost fully formed although an adult Deacon has not been seen.

Appearances

 * Prometheus (cameo, first appearance)