Cloaking

Cloaking is an ability available to terrans and protoss through both technological and psionic means.

Overview
Through the personal cloaking device, terran ghosts and spectres are able to cloak. The device is based on the stealth technology utilized by Wraith starfighters, which are also able to cloak. This technology was later applied to the Banshee.

Some protoss aerospace craft are able to cloak the units around them; examples include the Khalai Arbiter and mothership, while the observer remains hidden through an in-built micro-cloaking field. The Dark Templar are able to cloak themselves through psionic means. This ability has been described as "bending light" and "merging with shadows".

Gameplay
A cloaked unit is a unit rendered invisible to enemies, unless an enemy detector is nearby. These include burrowed units. Cloaked (and a few burrowed) units may attack without uncloaking; terran cloaked units require energy to maintain their camouflage, and the cloak will be disabled when it is depleted.

The ability to approach unseen, attack while invisible, and fade away makes cloaked units ideal for ambushes, raids on worker lines, and scouting.

Detectors are the normal method of revealing cloaked units.

When invisible, cloaked and moving burrowed units may be tracked by their slight "rippling" distortions. Invisible units retain their collision radius; their position may be given away if visible units must move around an invisible one. Detectors are still needed to target invisible units even if they are found these ways.

Detectors are not the only way to deal with cloaked units. Some special abilities affect or reveal cloaked units. Cloaked units are affected by splash damage; it is possible to attack a friendly unit with splash damage attack to damage surrounding invisible cloaked units. Cloaked units include:

StarCraft
Protoss
 * Observer
 * Dark templar
 * Any unit near an arbiter (but not the arbiter itself).

Terran
 * Wraith with Cloaking Field upgrade
 * Ghost with Personal Cloaking upgrade.

Zerg
 * Any unit which is burrowed.

StarCraft II
Protoss
 * Observer
 * Avenger (protoss)
 * Blood hunter
 * Dark templar
 * Any unit or structure near a mothership (but not the mothership itself)
 * Any unit or structure near a dark pylon (but not the dark pylon itself)
 * Arbiter (but not the Arbiter itself)
 * Corsair (Co-op missions mode) with Stealth Drive upgrade
 * Havoc (Co-op missions mode) with Cloaking Module upgrade

Terran
 * Ghost with Personal Cloaking upgrade.
 * Banshee with Cloaking Field upgrade.
 * Spectre
 * Wraith
 * Liberator (Nova Covert Ops only)

Zerg
 * Any unit which is burrowed.
 * Creep tumors once they finish building. They were usually uncloaked in the Wings of Liberty campaign.
 * Infested banshee

Trivia
Cloaking in StarCraft was possibly inspired by the Giant Sea Turtle and the Gnomish Submarine from Warcraft II. These underwater units could not be detected without air units, nearby towers, or other underwater units.