You can find the skull on Normal, Heroic, or Legendary difficulty. It won’t’ appear on Easy difficulty. [2] X Research source

You can find the skull on Normal, Heroic, or Legendary difficulty. It won’t’ appear on Easy difficulty. [2] X Research source

Don’t worry — as long as you met the criteria above, none of your actions earlier in the level will affect whether or not you can get the skull.

Kill all the Covenant in the room. Kill the Prophet of Truth. Extend the bridge at the end of the room and kill all the Flood. Don’t jump down the elevator shaft — you won’t be able to return if you do.

For easy reference, the only ring with a red section on it is “4. “[3] X Research source

You must always jump toward the bridge you extended. You won’t get the skull if you jump through the rings in the wrong direction. If you mess up, you must start from the beginning again (ring 4). You don’t have to start the whole level over.

As just one example, if you’re using the skull while fighting Brutes with other marines, you may hear one of them say, “Hey, I heard their weakness is bananas, do we have any bananas?” It’s possible to hear this without the skull, but it occurs much more rarely. [5] X Research source