The possession horror sub-genre has become a formula.  A normal family suddenly starts experiencing disturbing behaviour (usually from a child) that can only be described as otherworldly, cueing a priest or a similar follower of the good word to go through with an exorcism.  It’s the job of the production to rise above this predictability to offer audiences individual strengths (creepy imagery and atmospheric scares, sometimes a scene-stealing performance like Jeffrey Dean Morgan’s in The…