A state in which a person is controlled by a demon from the outside. This is to be contrasted with possession, in which is person is controlled from the inside. A demonically obsessed person is not inhabited by the demon, just yanked around by it. Think of it as the difference between pulling the strings on a marionette and a operating a hand puppet. If you were unfortunate enough to catch the movie Stigmata, the scene in which she's whipped by invisible forces on the subway is a good example of demonic obsession