"Savage. Extreme physical prowess. Essence
useful, must acquire."
The Tyrannozor is a powerful primal zerg lifeform. One appears in the Heart of the Swarm mission The Crucible. Killing it gives additional levels to Kerrigan.
Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, The Crucible (in English). 2013-05-16.