Effect: When either player dies in Co-Op on any difficulty both players will restart at last check point.

Where to Find: Spartan 117

How to find: In the area where you rescue Sarge, behind the prison cell is a large ledge. Got to the far right side and jump on the boxes, then onto the pipes to get up on the ledge, goto the far end of the ledge, turning two corners the skull is at the far end.