Smile

Dr. Rose Cotter works in a hospital psychiatric unit with the particular exhaustion of someone who has been giving more than she has for a long time. A patient named Laura is brought in claiming to be stalked by a smiling entity that no one else can see. During their session, Laura smiles broadly and cuts her own throat with a shard of ceramic. Rose watches her die.

Rose begins to see it: people smiling at her in public with a wrongness that is hard to describe — too wide, too fixed, too aware. Her colleagues attribute it to trauma. A detective she tracks down tells her he has documented a chain of suicides going back years, each preceded by the same reported haunting. The entity travels through traumatic witnessing of a death. Each new host has roughly a week. The only way to break the chain deliberately is to kill someone in front of a witness, passing the trauma on instead of absorbing it. Rose refuses.

She investigates her own history: her mother died of an overdose when Rose was a child, and Rose found her and did not get help in time. She has built her entire adult life around that wound without ever treating it. She goes to her childhood home, confronts the memory, and believes she has broken the entity's hold on her. She calls her ex-boyfriend Joel and tells him it is over.

She is not at her childhood home. She has been hallucinating for hours. She is at Joel's house, having driven there in a state she has no memory of. The entity has been controlling her perception. It manifests in front of Joel in its true form — enormous and wearing the face of Rose's dead mother — and destroys her. Joel watches. He has seen it now.