Ripper Swarms

In the fictional Warhammer 40,000 universe, the Ripper Swarm is the smallest Tyranid organism.

Biology

Ripper Swarms (or Rippers) are tiny Tyranid organisms designed to harvest all biomass left after the initial invasion. Their lives are short-lived, as they will throw themselves into digestion pools after their bellies are filled. Physically they resemble an immature Gaunt.

They are mindless in the sense that they only desire to consume anything they find. Where other Tyranids would revert to feral instincts when a synapse creature is unavailable, the Rippers will mindlessly continue their tasks, unmoved by any danger. Rippers are deployed at the end of an invasion, to strip the planet of any usable biomass. Once they have consumed all, they are dropped into digestion pools, where their accumulated biomass are absorbed, categorized, and used as building material for the next generation of Tyranids. They themselves will also consume Tyranid biomass, regardless of its source.