The term for a person who keeps staring at himself in the mirror for a very long time is "spectrophilia." Spectrophilia is a psychological phenomenon where an individual becomes fixated on their reflection, often spending extended periods staring at themselves in mirrors. This behavior can sometimes be associated with a preoccupation with one's appearance or body image and may be linked to certain personality traits or psychological conditions. It's essential to recognize that spectrophilia can be a symptom of underlying psychological issues and may warrant professional evaluation and support from a mental health professional.