火間蟲入道 Himamushi nyūdō is a grotesque yōkai which lives under floorboards and crawls out at night time. It vaguely resembles a Buddhist monk, but it has a long neck, sharp claws, a body covered in thick, dark hair, and a very long tongue which it uses to lap up the oil from lamps. Himamushi nyūdō bothers people who are working hard or studying late at night by jumping out of the darkness and scaring them. Although it doesn’t directly attack people, its presence is disturbing enough. It blows out the lights suddenly, and it licks up the precious lamp oil, making it difficult to continue working.