Drone

The drone is the zerg worker unit.

Overview
Drones stem from the savage gashyrr wasps of Eldersthine, absorbed into the Zerg Swarm to serve as resource gatherers. Over time they became drones, engineered with the larvae's ability to break down their own genetic coding and transform themselves into rudimentary zerg structures. A transforming drone needs creep to provide nourishment and mass to support its new form.

Like the larva, drones are controlled by overlords who monitor their progress. Drones are usually single-minded about their tasks, diligently working through even raging combat.

Drones possess limited combat ability, but in a swarm, they can present a significant threat, attacking with claws and spines.

Known Drones

 * Drone (Unity of Races)

StarCraft
Drones "mutate" into the buildings they construct. The only way to stop a building from completing is to destroy it or to cancel it; in the latter event the drone is recovered and may be used for some other purpose. Once the building is complete the drone is deceased.

Drones benefit from burrow. Unless the enemy brings detectors burrowing can minimize the damage caused by a raid on harvesting operations. Once the enemy is repelled harvesting may immediately resume without requiring the replacement of all workers.

StarCraft: Ghost
The drone was present in StarCraft: Ghost's single-player mode. Nova could mentally control a drone in order to "infest" a computer terminal, then use the terminal to control objects such as a robotic arm.

StarCraft II
In StarCraft II, drones are rallied separately from other units with the "G" key, which can be combined with automine. Unlike their predecessors, they no longer have a ranged attack.

Unlike most other zerg ground units, drones do not gain a speed boost on creep.

When Kerrigan reaches a certain level in the heart of the swarm campaign drones can be morphed in pairs.

Development
In earlier builds of StarCraft II, drones were not required to build defensive structures, such a role having been taken over by the queen. Drones have regained their ability to create defensive structures.