I HAVE FOUND A SKULL IN OUT SKIRTS BUT WHEN I went back it wass gone wat it did wass warp me to a room were a elite witha sniper rifle shot me and killed ne ill tell u the dirrections to how i got there in outskirts when u get to the part after the hunters were there are the snipers in the dark at the back in that area kill all the guys and jump onto the purple think and look left there should be a leged that u could get to but when on look up there is a beam that u could jump on and get on and walk to wards the roof there will be an invisible wall but u should be able to crouch under it and geton the roof then go left i dont relly remember wat i did after that but theres a room with a tarp thing on it and in there there is a human sniper and amo for it and the skull o this is on lengendary dificulty and the skull brought me to aroom with an elite who just shot me stright in the head but when i looked again it wasnt there some one please let me no about these skull i hope they unlock a new single player level that fixes the ending cause it sucked. kk thats all i no hope u figer it out thanks alot bye