Yōkai (妖怪, "strange apparition") are a class of supernatural entities and spirits in Japanese folklore.

Yōkai (妖怪, "strange apparition") are a class of supernatural entities and spirits in Japanese folklore. The kanji representation of the word yōkai comprises two characters that both mean "suspicious, doubtful", and while the Japanese name is simply the Japanese transliteration or pronunciation of the Chinese term yāoguài (which designates similarly strange creatures), some Japanese commentators argue that the word yōkai has taken on many different meanings in Japanese culture, including referring to a large number of uniquely Japanese creatures.