I read once that the human brain is incapable of creating a brand new person in it's dreams. Apparently everyone in our dreams is someone we have seen before, we may not know the person, but at least have seen them. So say, you are being chased by an axe murderer in a nightmare, the face of that murderer could be anyone from a friend, to someone that served you in a shop, or even that you just passed in a street, it will never be a creation of the brain itself but more a subconscious memory of someone.
That's pretty neat Kathy, it almost sounds like a comic-book super power. In fact it's much cooler than a lot of the powers that some of those characters have. Think of what your superhero name could be... 'The Tingler'