Difficulty: Legendary
Level: Quarantine Zone
Word: Sputnik
Effect: Lower gravity

From the start of the level, look to your left for an Elite. To the left of the elite there is a tunnel. Head into the tunnel and go straight until you reach a cliff. Now turn left and follow the cliff till you reach a rock wall. To the right of the wall and the cliff is a narrow passage, skull is at the end of that passage.