I'm camping alone, asleep in the tent when suddenly a twig snaps outside. My eyes fly open and I blink several times, trying to make sense of a dim shadow cast against the thin nylon wall of the tent. I shut my eyes tight and withdraw silently into the sleeping bag, but the image has been burned into my mind and the only thing I can do is peep out again, hoping against hope that I dreamed the whole thing. But no, it's still there and now I can hear it breathe.