Primal hives are primal zerg structures used to spawn primal units in the "Waking the Ancient" mission. They are capable of attacking, and can uproot themselves and become mobile.
The "Rude Awakening" achievement can be earned by destroying four primal hives in the mission.
Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, Waking the Ancient (in English). 2013-03-12