The Mutalisk has changed little from its original incarnation as the spacefaring Mantis Screamer of the desolate Dinares sector. Mutalisks form the primary flying force of the Zerg, making hit-and-run attacks against vulnerable installations and wheeling across the skies in prodigious numbers above Zerg Hives or land-based forces. Mutalisks are agile and dangerous opponents. They can attack foes both in the air and on the ground by expelling a voracious symbiote known as the Glave Wurm, which can rapidly strike at several opponents as it explosively disintegrates. In large numbers or against weak defenses, Mutalisks are a deadly threat.