This side quest starts as soon as the game begins. five Infestors are spawned at random about the map. They wander aimlessly until killed. They can cliff climb, and on higher difficulties, will lay baneling eggs or even Burrow to escape players. Each Infestor killed reduces the Zombies' spawn rate by 2 Zombies per minute for each Infestor killed. The Infestors themselves reward all players a chunk of in game experience upon their death. Once all are killed the team is rewarded with 2 or 3 experience.