The only difference between obsession and the last stage, possession, is one of degree.
Together they've been investigating paranormal activity for over fifty-five years throughout the United States, Canada, Mexico, Scotland, and Europe, to name only a few places. If you study these stories and these phenomena carefully, you find that one opens the door to infestation, obsession and possession by careless fixation on the occult, playing with the Ouija board and toying with Satanism or black magic.