We talked about yuru-chara last time. Their designs or cultures are also heavily influenced by yōkai stories or Japanese folklore. One of the most famous yuru-chara based on yokai is kappa.
A kappa (meaning river child), also known as kawatarō (川太郎), komahiki ( horse puller), kawatora (river tiger) and many other names, is a famous yōkai demon in traditional Japanese folklore. The name Kappa is a combination of kawa (river) and wappa (child). In Shintō, Kappa are considered to be one of many water deity or gods. In Japanese Buddhism, Kappa are usually a kind of hungry ogres. Kappa are distinguished as having a small pool of water suspended on top of their head, signifying their life force and habitat.
Kappa usually have characteristics as mischievous troublemakers. They are famous for all kinds of pranks ranging from looking up women's kimonos, to drowning people and animals, kidnapping children, raping women and even at times eating human flesh. Kappa are not entirely against human beings. They are curious about human civilization, and they often can understand and speak Japanese. They may make friends with human beings in exchange for gifts or offerings of nasu (Japanese eggplant), soba, nattō (fermented soybeans), and especially cucumbers, Kappa's traditional favorite food.
Japanese will write their names or their children's names on cucumbers and toss them into waters as sacrifices to Kappa so they will not harm the family. It is also customary sometimes to eat cucumbers before swimming as protection. However, some others believe this will actually seduce Kappa to attach the swimmer.
Probably it is because the controversial traits of Kappa as a god of river, there are a lot of stories to tell in Japanese culture of Kappa and thus they might be the most well-know Yokai among all ages. And definitely, there are kawaii version of Kappa to make children fear less of them, e.g. the mascot for @Jozankei Onsen 定山渓