- Yokai are supernatural spirits or demons in Japanese folklore that manifest in various strange or bizarre forms. Some examples described include kappa, nurarihyon, and nureonna. - Stories of yokai serve to explain unusual phenomena and also teach lessons through figures like momonjii which parents use to scare misbehaving children. - Many yokai were thought to possess powers over certain domains, like hyakume which protected shrines and dorotabo who haunted his old lands, and live on in modern Japan through celebrations and art depicting their forms.