Overseer

The overseer is a zerg unit evolved from the overlord.

Overview
Overseers are genetically-altered overlords that have a mass of additional sockets filled with highly evolved optical receptors with hypersensitive retinas. These “eyes” have been through many iterations, each developmental cycle improving upon the preceding one’s optical evolution. The zerg are obsessed with detecting subtler motions and more advanced camouflage techniques, and this latest evolution allows the overseer to detect any hidden enemy units, including those that are burrowed underground or cloaked. Overseers can also carry or give birth to changelings.

Unlike most other zerg breeds but like overlords, overseers have the ability to act with appropriate judgment, but are severely limited in their mental flexibility.

Game Unit
The overseer loses the ability to excrete creep or transport units, but gains the ability to create changelings. It continues to provide control and has faster movement.

Heart of the Swarm Campaign
Sarah Kerrigan's forces never create overseers. Detection was never required in the campaign.

Special Overseer Strains

 * Spotter