The Funayūrei

The Funayūreiare, also known as the Funayūrei, are dangerous water-spirits in Japanese mythology. They are believed to be the ghosts of people who have died at sea and approach people on boats and ask to borrow a Hishaku, a utensil for scooping up water. If they are given a ladle, they will pour sea water into the boat until it sinks.

This is similar to the idea of Sirens in other cultures, who also had a tendency to lure sailors to their doom - like the Sirens these tales were likely designed to symbolize the dangers of the open sea: the sea is also often seen as the home of evil spirits (such as the Leviathan of Christian folklore or the Fomorians of Irish mythology).