Xenomorph

Specimen designation XX121, and every crew that ever catalogued one is dead. The cycle is engineering at its cruelest: the egg waits (years, centuries, it does not care), the facehugger takes a host, and what bursts out grows in hours into the perfect organism: biomechanical carapace, acid for blood, a second set of jaws, and no conscience anywhere in the design. It does not hate. It does not negotiate. It builds hives in the dark of stations and colonies, serves a queen, and treats every other living thing as either a threat or a womb. The company that keeps trying to weaponize it has never once collected. In space, famously, no one can hear what happens next.