There is a location in the high school with stairs going down. At the end of that platform is another platform that is too far to reach. Do not try to reach it as you will lose a life, even if you try from above. Collect all the other bones and wait in a safe location until you run out of Zzz's. Then, change into the warlock, find that unreachable bone, and get it. Go back and find a boom-box to wake up again.