Simple as that, I've heard a couple of times people mentioning "Lost souls" when you OBE. i didn't fully understand it but what i know, is you get out of your body when you do an OBE, and a lost soul enters your body, while you are outside. I've also heard thats the way you get up and sleepwalk.

What are lost souls? where do they come form? what are their purpose?

If anyone knows more about Lost Soul's please post, would be cool to know something new.