In campain, On the level Outskirts with the covenant "Shadows" in the tunnels...well if you do know what im talking about hijack a ghost when you are at the beach part of the level, get to the tunnel, dont take the time to kill anything when you see the cars with ghosts just wait fool around for about 5 minutes(works better with 2 people), after about 5 minutes jet forward soon you will see that the cars have stop and the drivers have gotten out of them. Dont destroy the cars what ever you do, get out of the ghost kill all the guys then jump on the back of the cars, if they are not destroyed it will say something like "get in shadow turret" once you are in shoot the walls and stuff...it shoots like an alien turret but fast like a warthog machine gun turret it is awsome!!!