Bakekujira

The Bake-kujira (化鯨, literally "ghost whale") is a mythical Japanese yōkai from western Japan.

It is supposedly a large ghostly skeleton whale and is said to be accompanied by strange birds and fish.

Legends
In one story a fisherman tries to catch it with his harpoon but the harpoon sailed right through it and the Bake-kujira floated away. In other stories people say that the Bake-kujira brings a curse and general misfortune to the area where it is spotted.