The Creep Colony are Zerg structures that extend the Creep, on which the Zerg can place its buildings. It can also morph into two types of static buildings:
- Sunken Colonies, which attack only ground targets
- Spore Colonies, which attack only air targets and provide cloak detection
Creep Colonies can be used for both defensive and offensive purposes, since they can be built on any existing Creep, whether the Zerg player's own Creep or that of the Zerg opponent's (i.e. in a ZvZ match-up). Placement of Creep on a Zerg opponent's is uncommon and usually only utilized in situations where the Zerg player's own attack units are attacking simultaneously, with the Creep/Sunken acting to attack in a supplementary fashion.
In defensive formations, Creep Colonies are often placed near chokepoints and important buildings such as expansion Hatcheries, then morphed into Sunkens or Spores. Creep Colonies are rarely built for the primary purpose of extending the Creep, as existing Hatcheries usually provide sufficient Creep for the construction of other Zerg buildings.
In ZvT match-ups, it is common for Creep/Sunkens to be built in the early to mid game to counter Bio Terran attack forces. They are vital in holding off an attack if the Zerg player intends to opt for higher technology units such as Mutalisks in the 3 Hatch Mutas build order.
In ZvP match-ups, Creep/Sunkens are often built in the early game if the Zerg player elects to go for multiple expansions, such as 5 Hatch Hydra (vs. Protoss). Creep/Spores are also common in this match-up to provide anti-air defense against heavy Corsairs and/or Corsair/Dark Templar (vs. Zerg) strategies.
In ZvZ match-ups, it is less common to see Creep being built, except to supplement in situations where the Zerg player is slow in Spire construction, thus morphing the Creep into Spores.