The Japanese water imp with a dish on its head is the kappa.
Kappa are water-dwelling yōkai traditionally said to inhabit Japan’s rivers and ponds. Their familiar modern appearance is roughly humanoid, often green or scaly, with webbed hands and feet, a turtle-like shell, and a shallow depression on the top of the head. This dish, or sara, is believed to hold water and supply the kappa’s strength.
According to folklore, spilling or drying the water in the dish can severely weaken a kappa. Stories describe them as dangerous beings capable of drowning people and dragging animals into rivers, but later traditions often portray them as mischievous rather than purely monstrous. They may be challenged to sumo wrestling and are famously fond of cucumbers.
Kappa legends vary by region, including differences in color, body shape, and local names. In some communities, the creature is connected with suijin, or water-deity worship, and offerings are made to placate it. The dish is therefore more than a visual novelty: it reflects the kappa’s close relationship with water and the danger of losing that vital supply.
Kappa are sometimes confused with tengu, but tengu are primarily mountain and forest spirits, whereas kappa belong to waterways.