The ash worm is a burrowing life form native to Ignus, where one killed the local broodmother. Its ability to quickly burrow through the crust was useful for the zerg's swarm host units to assimilate, creating the creeper strain.[1]


  1. Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, Swarm Host Evolution (in English). 2013-03-12.