Lurkers are awesome units new to Starcraft. They came with the Broodwar expansion and posed a great help for any zerg defensive or offensive army. Lurkers are a little high in the technology tree requiring a hydralisk den, a lair, a lurker aspect upgrade, and a hydra to morph into a deadly lurker. Lurkers in total cost 125 minerals and 125 gas.

• Lurkers work best in groups of 4 and above. In a tightly packed formation, they can kill off a tightly packed line formation of infantry units in moments.
• The splash damage of lurkers do no affect your own units, so lurkers are very good for defense. Position them near sunken colonies so they can support each other. The sunken colony deals the great blow and the lurker finishes it off.
• Never leave your lurkers unattended especially unburrowed.
• A great way to attack using lurkers is to attack a bunch of zerglings and squads of hyralisks, while the enemy is busy fending your units off, the lurkers sneak rigth in the middle of your opponent's base and burrow them.
• Another tactic is a heavy hydra attack, inside the enemy base, use some hydras to morph into lurkers for late added firepower. Be sure no to morph too many because it will cause a great loss of immediate offensive power.
• Upgrade missile attacks, this makes +2 damage to the splash damage of lurkers and +1 damage to hydra spines.
• Take advantage of cliffs, burrow lurkers near ramps on highground to prevent enemy passage. If can successfull block an enemy base's choke point. His expansion will be crippled.
• Be wary of air fighters as they can hurt your lurkers badly.
• Destroy terran comsat station first if he has no turrets. Your lurkers best work if they cannot be seen.
• The element of surprise is a deadly weapon, if your opponent does not know that you have lurkers, you can devastate his entire base or army if he is not prepared.