A handy trick for taking out large clumps of siege tanks defending a base or position. The more tanks there are and the more closely they are packed together the more effective this tactic will be. Using a queen, spawn broodlings one of the tanks, killing it. As the broodlings emerge the other tanks will fire on them, damaging and killing the surrounding tanks. Keep in mind the amount of damage tanks do and that of undefended from the air, only 2 or so queens can take out about 12 siege tanks. This will also frustrate the hell out of the terran player.

CreepColony's Opinion: Very helpful if you are going hydra.