hi Kirk:
the book named Journeys out of body by Robert A Monroe
should explain this phenomena pretty well.

When I read it I began to understand out of body experiences more even though I have never actually done it myself.

There are several stages involved. The most important to remember is to keep a loving feeling in your heart and mind and you will find that these "evil" entities will go away. They are like bees, only interested in you if you are showing fear. They are harmless.

Feel free to contact me if you have questions.
Cora.