Would this dream scare the hell out of you? What could possibly explain it (reasonably)?

I am no psychologist, but I do know that dreams are a reflection of the subconscious part of the brain. This may sound weird but ask ghost hunters to inspect your house. Yes they do exist, but their job is not to hunt ghost it's to try to disprove them and explain other things that may cause "paranormal activity." Also if you're close to any source of high energy like power lines, that messes with the brain and cause paranormal allusions. I would talk to a counselor she can put you under sypnosis usually it brings out things in your subcounsion that can contribute to your dreams that you may not even realize. NO IT'S NOTHING LIKE WHAT YOU SEE IN THE FOURTH KIND.