You are a monster. You have fangs, psychic powers, impenetrable skin, all the usual stuff. And you have a hunger, something that burns deep within you that causes you to hunt humans. Hunt them carefully and quietly because if you rile them they will turn on you.
In You are our Prey the characters play the part of monsters that need humans to survive (in some way or another). Each character gets to select or randomly determine some funky powers from which to make his monster.