An utterly alien race in Warhammer 40K. Racially, this group bears some resemblance to the Xenomorphs of H.R. Giger. Utilizing a hive mind, this race crosses galaxies in their great organic hive fleets. They are continually evolving by consuming newly encountered species and adapting the consumed genetic material for the betterment of the hive.

They bear some resemblance to the Zerg of Starcraft but predate them by some years.