Headcrabs

Headcrabs



Headcrabs are a parasitic lifeform used by the Union as a biological weapon. The headcrab attacks its victim by fitting its mouth-like beak around them, and burrowing into their nervous system. The result is essentially a zombie - but their hosts oxygen starved brains lead to these 'zombies' to be inefficient at simple motor control tasks, forcing them to attack via simply striking their target.

The headcrab'ss origin is unknown; whether they preyed on human-like creatures on their home world or were developed by the Union specifically for Earth is unclear.

For use as a biological weapon, the Union simply loads them into shells and launches them into target areas, allowing the headcrabs to escape and kill the local population.