Ultralisk Cavern
The zerg ultralisk cavern is a shelled structure in which there are numerous high-radiation deposits and other dangerous substances. It is in this extremely hostile environment that the ultralisk gains its toughness. In addition, it provides all of the genetic coding for the larva to morph into the breed itself.
StarCraft: Brood War
During the Brood War, the ultralisk caverns could also provide additional genetic mutations for Anabolic Synthesis (for faster movement) and Chitinous Plating (for improved armor).
Co-op Missions
The ultralisk and ultralisk cavern used by Kerrigan in Co-op Missions. Additional upgrades for the ultralisk become available when Kerrigan reaches Level 13.
ZERG – THE SPAWN OF THE SWARM
WILD. FATIGUE. FLEXIBLE.
Once artificially created by the mighty Xel`Naga, the Zerg would eventually lead to their demise and become a threat to the entire galaxy. Because of their collective consciousness, this species is often referred to simply as “the Swarm.” In their quest for perfection, the Zerg adopt advantageous and superior gene strands into their own gene pool, wiping out “inferior” species in the process.
Zerg Buildings
While the Protoss rely on technological superiority and the Terrans on their adaptability, the savage Zerg rely mostly on pure mass. The mostly lightly armored creatures usually pounce on their opponents from all sides on the battlefield, leaving only a picture of devastation in their wake.