Ancient Japanese Sea Imps, The Kawataro were said to have heads full full of water. They liked to play tricks on humans. Once thoroughly amused and relaxed, The Kawataro would then pounce on their human prey (eating them!). They were said to expert wrestlers as well. A way to escape a Kawataro was to pierce their head (to cause the water to drain). This weakens the Kawataro so one can escape.
