The Lurker is a unique unit added in the Brood Wars expansion in that it attacks while burrowed with linear splash spikes. As such, the Lurker is the only Zerg unit that can burrow without the appropriate upgrade being researched from the Hatchery. The Lurker is morphed from the Hydralisk after the appropriate Lair-tech upgrade is researched from the Hydralisk Den.
The Lurker's attack is a spine attack that shoots outwards in a line from the Lurker towards its target. Because of this, it is unique in that it is the only attack in StarCraft that can actually be dodged (but not the only one that can be canceled) once the attack has been fired. It is useful to note that the Lurker's spine attack actually has a larger damage range than the attack range of the Lurker. That is to say, if you were to attack a unit at the maximum range of the Lurker, the spinal attack would actually extend slightly past that range and hit a unit on the far side of the target. This can be useful when harassing workers from a cliff that is slightly out of range by attacking a Pylon or other building/unit that is in range while the Probes are not.
Lurkers are almost never used in ZvZ due to the fact that ZvZ are usually low economy Mutalisk and Zergling games. However, if a player does go for a Hydralisk build, Lurkers may be used, especially Hold Lurkers. Hydra-based builds usually depend on a mid-game timing attack, so if this attack does not determine the winner, and the player continues teching to Lair, the addition of a few Lurkers can help against an opponent who is producing significant amounts of Zerglings.
Practically speaking while it is rather effective against groups of Zerglings, Zerglings can actually close the distance quite quickly. Massed Lurkers are needed to head this off and that is difficult against Zerg base pressure without Mutalisk, which cannot really be gotten at the same time. It has more use when the Overlords can be killed off, although it's hard to have the flexibility to do so without putting the army production behind what in ZvZ become game-winning battles. Because Overlord speed is not researched, as it usually is to mass Mutalisk, the Lurker can be a fairly competent defensive unit if Overlords can be cleared.
Lurkers are extremely powerful in the rare early-late-game ZvZ once Defilers come into play because it removes the common massed army unit, the Mutalisk from play in a battle. The only units capable of damaging Lurkers under dark swarm are Ultralisks, Zerglings, and other Lurkers, and massed Lurkers can take care of Zerglings rather easily.
Lurkers are invaluable in ZvT, oftentimes being combined with other units (primarily Zerglings) in standard army compositions for some builds. Because Terran so often goes infantry when facing a Zerg, Lurkers' high damage and splash are used, in combination with good positioning and flanks, to flatten opposing infantry armies. Lurkers see usage beyond the midgame and well into the late game to defend expansions from Terran infantry. They can be paired with defilers to force the Terran army to retreat since firebats are ineffective against them under swarm and marines cannot hit them. Lurkers are generally used with the Nydus Canal to quickly bring reinforcements to an expansion that is being attacked. However, it is important to note that Lurkers are only good in groups if they have a great positional advantage (such as sitting atop a ramp). Despite their high damage, focus fire from a group of medics and marines bring lone lurkers down quickly enough. Lurkers see offensive usage until Ultralisks are hatched.
The immobility of the Lurker is generally exploited by the highly mobile Terran bionic army as it can retreat upon seeing Lurkers burrowing. Therefore, the Zerg player must either pull his Zerglings back or unburrow the Lurkers and continue the pursuit.
Lurkers are rarely used against Terran mech because of the long range of all Terran mech units and their relatively high hit points as compared to the Terran bionic army. The one somewhat popular use is Hold Lurkers, which can punish Mech armies which aim for a mid-game push, such as Flash's recent Goliath and M&M strategy.
Against the 2-port Wraith build by Terran, Lurkers are a common response because the 2 Port Wraith build runs off of 1 base. Generally, the scans used by the scanner of the Terran is used to see Zerg tech and find Zerg expansions, so they are generally not used to check for Hold Lurkers. Therefore, if Lurkers are gotten fast enough, then Hold Lurkers may be placed at the Terran natural which can decimate the Terran army if he is not careful.
Lurkers eggs morphing are also used to block ramps and prevent marines from moving up the ramp and taking out an expansion.
Lurkers are a staple of the Zerg army in the midgame against the Protoss since Lurkers are a very good counter to large numbers of the Protoss Zealot, and can damage Dragoons somewhat effectively depending on the situation. Against Protoss, Lurkers are most effectively used when containing a Protoss in a spread-out field because of the tendency of Lurkers to clump when they are moved as a group. Since Lurkers are unable to move once they are burrowed, a single storm can damage a large number of Lurkers if the Zerg player is not careful. To support a Lurker army, Overlords and Scourge might be paired with the Lurkers so that Observers can be sniped by scourge so the Protoss has no method of detecting the Lurkers.
Certain Zerg vs Protoss strategies will also depend on turtling on several bases with a Sunken/Spore/Lurker defense. The narrow choke amplifies the power of lurkers, and a Spore colony placed slightly ahead of the lurker positions can force out observers, making the defense hard to break.
Lurkers are staple units for Zerg until the late game, when Ultralisks replace them in the Zerg army.
- Damaged Hydra eggs that morph into lurkers re-acquire full health when they finish
- The mineral, gas, supply, and time cost is also considering the cost of the Hydralisk used to make the Lurker.