Lair

The Lair is the second major step in the evolution of Zerg breeds, providing increased toughness and extended access to the stored genetic knowledge of the Overmind than the Hatchery. The Lair has many of the same characteristics (producing Larva maintains the Creep, digesting minerals\gas, mutates Burrow upgrade) but also provides additional upgrades for the Overlord, which include the Ventral Sacs (transporting ability), Antennae (increased sight) and Pneumatized Carapace (faster movement). A Lair can be mutated into a Hive.

The Lair in StarCraft II
The Lair upgrades the armor of the Overlord and Overseer as well as upgrading the speed of the Overlord.

The Lair has 1800 hit points and it costs 150 minerals plus 100 Vespene to upgrade from a Hatchery. It requires a Spawning Pool. It takes 60 seconds for a Hatchery to evolve into a Lair.

Upgrades
Evolve Overlord
 * Research Cost: 150 0 100 140 seconds
 * This ability increases the armor and speed of the Overlord.

Evolve Overseer
 * Research Cost: 25 0 25 40 seconds
 * This ability increases the armor of Overseers.