The queen possesses numerous tentacles, a sinuous head, and a stretched skin membrane. During the Great War and Brood War, these queens, as with the overlords, were subordinated to the cerebrates to help administrate the Swarm. Queens usually stayed near the hives where they oversaw maturing zerg and drone activities. Their primary role was as an infestation specialist. These queens are capable of operating in the air and on the ground.
On the battlefield, one of the queen's primary functions was to implant parasites in its enemies. Able to be launched from a distance, a tiny, remora-like parasite attached itself to the target, 'bonding' with it should the target be organic. The parasite allowed higher zerg strains to see whatever the host saw and at the time of its first use in the Koprulu sector, could not be removed without killing its host. The parasite can also provide a link for the zerg to "talk" to the host and serve as a vector for the hyperevolutionary virus.
With the arrival of the United Earth Directorate in the Koprulu sector however and the introduction of nano-conveyed anesthetic and attenuated laser technology they brought with them, the parasites could be safely removed if detected by medics. However, by 2503 at least some parasites could not be detected by terran technology.
The queen can also infest other creatures, causing them to expire and broodlings to emerge from them. It takes time for the queen to produce these creatures, though the rate of reproduction was able to be increased through the use of gamete meiosis. In the meantime, the queen is able to spray its victims with a thick mucus, slowing them down drastically before dissolving. Most feared of the queen's abilities, however, is its ability to produce parasitic bio-toxins. These could be sprayed onto individual targets at close range. Once released onto a structure, these toxins quickly infest the facility, bringing the structure and those inside it under the control of the zerg. The only safeguard against this ability was that the structure had to be in a state of disrepair before the toxins could be deployed.
The queen was derived from the Arachnis brood-keeper. While the brood-keepers were capable of laying clutches of eggs, such an ability was deemed unnecessary for the queens, as their role in the Swarm was not tied to reproduction.
Following the Brood War, a small number of older queens continued to exist. However, their role and biology was re-purposed into a new form, which was more physically resilient, and focused on nurturing colony sites.
A queen has no normal attack and uses its speed to escape danger. The queen may be a nuisance raider using Spawn Broodling against high-value units like siege tanks, lurkers, ultralisks and dragoons or harass drones and scvs that are harvesting minerals or gas. Spawn Broodlings may also be used on zerg eggs.
It is relatively fragile for cost. Defensive counters include groups of air units and enough automated defense structures to either prevent a queen from sneaking into a base or kill it before having a chance to escape.
Converts a badly damaged terrancommand center into an infested command center. A queen moves over a flying or grounded building and disappears for a short time. Control of the building only changes when the infesting queen reappears. The now-infested command center is restored to full health.
Attaches a parasite to target unit or critter. Infecting player sees everything the infected unit sees. Infected detectors reveal cloaked and burrowed units. Infected cloaked or burrowed units are always visible to the infecting player.
All units in the 4 x 4 targeted area when Ensnare is used will have their movement speed reduced by half and attack cooldown increased by half. Cloaked units caught in the area will also be revealed for the spell's duration.
According to Bob Fitch, the role of the hatchery was initially going to be the taken by the queen, who would lay eggs like the Queen from the film Aliens. However, it was demed too hard to get the look and feel of the queen in this role. The queen was changed to a ground unit, and later manifested as a flying unit.
According to the StarCraft manual, queens were utilized by the zerg before the Swarm left Zerus and were derived from the Arachnis brood-keeper. The wording is ambiguous: either the "queens" present on Zerus were derived from a different species or the brood-keeper was native to Zerus.