- Shoot a zombie's arm off in the easiest mission ever
- Teabag the ground until another zombie throws a skull at you to stop
- Pick it up
The Fog skull is the skull of the hardened space n00b named Sergeant Fog, who hated the motion sensor so much becasue noob Elites kept killing him with it. He later committed suicide, giving his skull to medical research. This research lab was located in Cold Storage, and was taken by an escaped zombie, who hoped to use it as a weapon during the zombie invasion.