It was a horror movie I watched in the eighties. It is about a demon that enters the body of a teenager by jumping up and down on the boy's belly. A family(father, mother, brother and younger sister) just moved in. The mother suspected something strange in the cellar that eventually touched her on the back. When the family had to leave the house for a visit or so, the boy stayed and reached to the basement following noises. Once in the cellar, the boy had to remove a wooden square off the wall as the voice was coming from behind. He found himself walking in a corridor at the end of which an arm extended out to shake hand with him. The boy ran out terrified. The invisible demon reached the boy to his room, mirrored him, forced him on the bed, climbed on his belly and started jumping up and down (pressing too hard on the boy's stomach) until the boy calmed down indicating the engagement with the demon. At that point, the fire blazed in the fireplace and the guns shoot right from their place. The boy watched how his head and neck now swell. The mother suspected her son had changed only when she noted the way he touches his sister. One night the boy was commanded of killing the family with a shotgun. The boy was eventually recovered on the hands of some religion man after severe manifestation of the demon. NOTE: the demon was not shown on the course of the movie till the encounter with the priest near the end. Any help please?!

Try Amityville Horror II: The Possession |