Description
My re-imagining of the Gonome from Half Life: Opposing Force as if it were to be brought into either Half Life 2's episodes, or a sequel.
When the Combine's suppression field was was shut down by the Resistance, humanity's reproductive functions were not the only thing freed from chemical chains.
The invasive Headcrab parasite's lifecycle had been halted during their weaponization against human rebellion to ensure control of their spread, but it seemed a return of the hosts' reproductive proteins undid the locks on the Headcrab's own puberty. While Combine created variants such as Poison and Fast Headcrabs were stunted due to heavy modification, the "pure" variants were able to undergo metamorphosis.
XY chromosonal Headcrabs fuse to their host and commence an intense mutation of the body. Although imperfect due to the Combine's damage to their genetics and humanity being a new host species, the Gonome form is no longer a shambling zombie but an effective predator.
Gonome are capable of out running human prey and can easily overpower with it's great strength and curved claws. The "head" has sprouted a lining of small eyes in order to better sense prey. The torso has developed into a proper alien mouth, able to bite and hold prey, and contains a modified intestinal structure that can launch acidic projectiles. The upper body has shifted to better protect the head as well as create more room for it's new maw.
Gonome are more intelligent than other Headcrab forms and will actively herd prey into hordes of zombies
XX chromosonal Headcrabs, rather than fuse to the host like their counterparts, slowly deform and bloat the host into an eggsac as their main body overgrows the host and develops a shell. Gonomes that desire to mate will assist the Proto-Gonarch in aquiring enough nutrients to grow into sexual maturity, bringing prey directly into her chosen nest. Though this young Gonarch has a shell tough enough to withstand most firearms, her host body leaves her hobbled, requiring the aid of the Gonomes and zombies to defend her until she becomes a reproductive organic tank.