Umibōzu
Umibōzu (海坊主; Japanese pronunciation: [ɯ.mʲi.boꜜː.(d)zɯ, ɯꜜ.mʲi.boː-], lit. 'sea monk') is a yōkai from Japanese folklore that has the form of a giant, black, human-like being. Little is known of the origin of umibōzu but it is a mythical sea-spirit creature and as such has multiple sightings throughout Japan.