A kappa is a creature from Japanese folklore, often depicted as a water-dwelling being resembling a turtle or amphibian. It is known for its distinctive features, including a dish-like depression on its head that holds water, which is believed to be the source of its power. Kappas are often associated with rivers and ponds, and they are known for their mischievous behavior. In folklore, kappas are said to challenge humans to wrestling matches and can be both helpful and harmful. They are known to enjoy cucumbers and can be appeased by offering them this food. Despite their playful nature, kappas can be dangerous if provoked.