Thanks for all the info, guys!

Spiderman_859, thanks for the detailed info on WILD. I do have one memory of when I was around 6 when I lost all feeling while falling asleep and seeing a boar/pig-like thing slowly walking at me. (although it looked weird, like it had been drawn on a chalkboard with multi-colored chalk) and when I really attempted to move it disappeard. the sights and sounds aren't that scary to me (I could always have someone else in the room with me) but what I worry about it the feeling. I've heard people say before they feel like their bodies are being ripped open and that kind of thing. Is this true? if so, how painful can these things get?