Baku is a term used to describe a type of mythical creature that has the ability to eat dreams. The concept originated in Japanese folklore and refers to creatures with long necks, large heads, and sharp fangs. They are said to roam the streets at night, searching for sleeping people whose dreams they can consume. In some stories, bakus are depicted as harmless creatures that simply eat bad dreams, while in others they are portrayed as malevolent beings that feed on good dreams too. The word "baku" is also used to describe a type of Japanese therapy that involves talking about one's dreams and expressing emotions related to them.