The Hydralisk Den is an early to mid game Zerg tech building that allows the Zerg player to create Hydralisks. The Hydralisk Den does not produce units directly, but rather enable Hydralisk morphing at the Hatchery. The Hydralisk Den allows upgrades to the speed and range of Hydralisks.
The Hydralisk Den allows the research of three upgrades: Muscular Augments for Hydralisk speed, Grooved Spines for Hydralisk attack distance, and Lurker Aspect for morphing Hydralisks into Lurkers. The Lurker Aspect upgrade also requires a Lair-tech upgrade.
In the ZvT match-up, the Hydralisk Den is built early on as it is very important in the early game to produce Hydralisks for defending against Mech Builds. Against more common Bionic Terran Builds, the Hydralisk Den is built slightly later to allow Lurker production.
In the ZvP match-up, the Hydralisk Den may be built early on to execute an all-in aggressive rush on a fast expanding Protoss, or by mid game in a more common Hydralisk-heavy strategy such as the 5 Hatch Hydra Build.
In build orders involving an aggressive Lurker rush, particularly against Terran opponents, the Hydralisk Den usually starts building when the Lair is near halfway done.
It is common to incorporate the Hydralisk Den into the Zerg Sim-City. For example, it is used to block off attacks by Zealots while Sunken Colonies that are positioned behind the Hydralisk Den can deal heavy damage to the attacking force.
- The Hydralisk den is the only basic building in the game that requires vespene gas.