The Devil in Silver by Victor LaValle

Pepper is mistakenly committed to a grim psychiatric facility in Queens, New York, where he soon discovers a terrifying supernatural creature stalks the halls at night. Alongside a courageous fellow patient, he must fight not only to survive the monstrous entity but also to retain his sanity against a broken healthcare system. This gripping blend of psychological thriller and dark fantasy explores themes of institutionalization, humanity, and resilience.