Director David Robert Mitchell's It Follows centres on a college co-ed named Jay who goes on a date that turns deadly. Jay's new beau, Hugh, claims he's being followed by a force no one else can see. He eventually transmits the curse of this unseen entity onto Jay through sex; whereupon, Hugh explains the supernatural being can take the appearance of any person seen by the eyes of the cursed but will remain invisible to others. If the force catches Jay, it will kill her and pursue Hugh as the previous person to have passed the demon along.
Part of what makes It Follows terrifying is the idea that the invisible nature of the attacker makes it impossible for anyone to truly provide aid to the heroine. There's a similar feeling of helplessness for the Wilsons and the audience in Us because we all know from experience that no one can help us with our personal demons except ourselves.
You can watch It Follows on Amazon Prime.