IT IS A SKULL THAT GIVES U MORE GAMESCORE WHEN U pick it up. go on the lever the storm at start. go thru the tunnes and bluildings till u get out in a big open erea. u will see 2 wraits. dont destroy them. if u do the skull will go away.u can only kil the gunner not the driver. u will see a round short building. get a worthog and drive next 2 it. crouchjump on 2 the building. the skull is ontop. press rb to pik it up and get an attchevemant