Uwan

An uwan(うわん) in Japanese folklore is a disembodied voice that inhabits old, abandoned temples and homes. According to ancient legends from Aomori Prefecture Japan, when a person enters one of these buildings, the formless yōkai shouts out an ear-piercing “Uwan!” The voice is only audible to people inside the building — those outside hear nothing. Since an uwan does not physically exist and only consists of sound, it poses no physical danger.