It is represented by a blue circle with a skull in the middle. The skull has a small holed skull on its forehead.
Effect: What was once resistance is now immunity. Enemies who where once resistant to certain weapons are now rendered nearly impervious. For instance, Brute Power Armor is resistant to most Human weapons; now it is far more difficult to kill a Brute with a human weapon. On the other hand, plasma-type weapons work extremely well against Brute armor. They are also impervious to headshots.
- Can be found in the level, Cortana, in the circular room. Where Cortana mentions that "she likes to play games too...". get on top of the ceiling of the room and the skull waits for you.
- It is suggested you jump off a deployable cover when attempting to claim this skull. Also, clear the room before you get the skull.
- There is a second skull on the level, called the Second Blind Skull. Carrying it with you through completion of the level grants you a spartan laser as a starting weapon on the next level.