Creep Colony

Zerg buildings in Starcraft. They have no prereq buildings and require 75 minerals to construct.

While Creep Colonies have no defensive value by themselves, they morph into the Zerg static defenses. They are also used to spread Creep, which non-Hatchery Zerg buildings must be constructed upon.

Sunken Colonies

Sunkens are ground-to-ground only and deal 40 Explosive damage with no attack upgrades. They morph from Creep Colonies and cost an extra 50 minerals (on top of the 75 for a Creep Colony), and this change requires a Spawning Pool.

It is notable that Sunken Colonies do half damage to Terran infantry, and due to the Sunken's cooldown time, one Medic can exactly reverse one Sunken Colony's worth of damage to one infantry unit (assuming sufficient energy for the Medic).

Krzysztof Baranowski was immortalized in Pi history for not dropping any Sunken Colonies during the epic battle against Slugfest, thus costing Floor Pi the tournament.

Spore Colonies

Spores are ground-to-air only and double as detectors. They deal a constant 15 damage and have no attack upgrades. Like Sunken Colonies, they morph from Creep Colonies and cost an extra 50 minerals. Unlike Sunkens, they require an Evolution Chamber as a prereq.

Spore Colonies have large sight and attack radius. Of the four ground-to-air static defenses, they are the most worrisome to Guardians.