Backwoods (1988)

While camping in a remote part of the forest, Jamie and his girlfriend Karen meet a strange, backwoods local man named Eben and his young daughter, Beth. When Jaime saves Beth's life, Eben insists on giving the two campers a good, square meal. Not wanting to seem disrespectful, the two campers reluctantly agree to follow Eben back to his home. But there they meet Eben's brain-damaged son William, whose obsession with Karen's long, black hair leads to a nightmarish sequence of events that will change Jamie's and Karen's lives forever.