A rare culture bound syndrome in which the subject (known as a pengamok) suddenly withdraws from his peers and family and gets violent towards people around him and may also use whatever weapon available to him. He is very difficult to be stopped at that stage. Ultimately he falls into a sleep or stupor and when wakes up having little knowledge of his violent behaviour.

The term comes from Malaysia in its origin. The phrase "running amok" also comes from this syndrome.