From SC2Pod
The Drone is the Zerg's peon unit. Just like all Zerg creatures they are slaves to the Overmind, but they are used to gather resources such as Mineral Ore or Vespene gas for the hive. Perhaps the most critical role of the Drone is that they are required to morph into Zerg structures for the hive.
Lore
The savage Gashyrr Wasps of Eldersthine were initially inducted into the 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 the Creep to provide nourishment and mass to support its new form.
Like the Larvae, Drones are controlled by the Overlords who monitor their progress through a type of instinctive telepathy. Drones are also unusually single-minded about their tasks, diligently working even through raging combat.
Drones have shown the ability to burrow into the ground when under attack. This technique allows them to remain concealed from their enemies while regenerating or waiting for reinforcements to arrive.
Mutates into
Basic Mutation (B)
Advanced Mutation (V)
Weapons
Abilities
Upgrades
 | Ground Carapace (C) [edit]
|
| | Level 1 | Level 2 | Level 3
|
| |  |  | 
|
| Minerals |  150 | 225 | 300
|
| Gas |  150 | 225 | 300
|
| Time |  160 | 190 | 220
|
| Requires
| Hatchery
| Lair
| Hive
|
| Researched at
| Evolution Chamber
|
| Affects | Baneling, Broodling, Changeling, Drone, Hydralisk, Infested Terran, Infestor, Queen, Roach, Ultralisk, Zergling
|
| Increases defense for Zerg ground units by 1.
|
Art and Renders
Screenshots
Older Screenshots
5 are carried per trip from normal minerals, 
4 per trip from a geyser with a 
