Evolution chamber

The Zerg Evolution Chamber is the result of the Overmind's view that complacency is the road to defeat, thus spurring Zerg evolution constantly. The Evolution Chamber provides a testing ground for the genetic code of lesser breeds, in short, helping to increase the offensive and defensive capabilities of the Zerg ground-based breeds. It is also required in order for the Creep Colony to mutate into a Spore Colony.

StarCraft II
The Evolution Chamber is set to appear in StarCraft II. Contains research upgrades for burrow (unlocks burrow), slime (Overlord), generate Creep (Overlord – this ability also increases Zerg buildings' Creep generation speed), and allows the Queen to produce Shriekers, increasing the range of the Sunken Cluster and Swarm Clutch abilities.