Don't worry about strange beings in your dreams. Everything that you encounter in a dream is a product of your own mind. It's not like there are (telepathic?) monsters stalking you in your sleep. As you become more active in dreaming and head towards lucid dreams (at least in my case) you have more blurring between waking an dreaming. For example I was attempting a WBTB and though it didn't work, I had about an hour there were I was slipping back and forth between waking and dreams where the two seemed meshed together, and I couldn't have told you for certain whether I was lying in my bed reminding myself to RC and when I was just dreaming I was in my bed.

But bottom line there's nothing in your dreams that can hurt you, anymore than something in a book your read or movie you see can hurt you. You're watching a television episode in your head, just one that you can sometimes take control and direct.