This article describes the Unit Type (StarCraft) or Attributes (StarCraft II). For information on the device, see here.
A detector is a unit or structure with the ability of Detection: it is able to reveal camouflage, permanently cloaked, burrowed, or hallucinations enemy units. Having enough Detectors across the map is an important aspect of any player's strategy, as they will provide intelligence on potentially fatal attacks from otherwise unstoppable hidden units.
While every race and faction has a mobile detector unit, they also have a passive stationary defense building that provides detection, such as Photon Cannons, Spore Crawlers, and Missile Turrets. Detector buildings lack the mobility of units, but make up for it by being much more durable and by being equipped with more powerful weapon systems. Regardless of which race a player uses, if the opponent uses cloaked or burrowed units, having a Detector in your army before engaging your opponent is pivotal.
Detectors can be stationary (buildings) or mobile (units). Once a detector uncovers a cloaked unit, any friendly unit can fire on it. This capability is especially critical when faced with a ghost targeting a nuclear missile or an arbiter providing cover for a number of units. Detector units trapped in Lockdown or hit by Optical Flares will lose their ability to detect.
Ensnare, Maelstrom, Plague, Stasis field and Lockdown will reveal cloaked protoss and terran units caught in their areas of effect for the ability's duration. Burrowed zerg units are unaffected by these abilities except Stasis Field while burrowed, but if hit by these abilities while above ground, they will be revealed if they burrow. Irradiate reveals all cloaked units it affects and also affects burrowed zerg units. EMP Shockwave will not affect protoss cloaked units or zerg burrowed units, but terran ghosts and Wraiths will be affected and lose all their energy, causing them to immediately decloak.
An infestor launches a projectile with a speed of 15; enemy units within the area of effect (2.25 radius) have their speed reduced by 75% and suffer 30 damage over 3 seconds. Cloaked and burrowed units are revealed.
Fungal Growth stops the use of Blink, Tactical Jump and prevents units from burrowing or unburrowing. Affected units can not be loaded into buildings or transports.