Gozu(2003)

Minami mistakenly kills a gangster associate of his named Brother. Almost as soon as the murder takes place, the body of the deceased man is gone, prompting Minami to conduct a search. While looking, he finds a mysterious isolated hotel where he decides to take a rest. Not only are the front desk clerks a bit strange, but even the ambiance feels unusual. Minami soon realizes he may have gotten more than he bargained for.