Ame Onna

Ame Onna are malevolent spirits from Japanese mythology that are considered to be either fallen lesser rain-goddesses or a type of yokai that haunt the world during periods of rain (in some tales they are the reason for said rain). They hunt down children to devour, a trait they share with many witch-like monsters across the world, with a number of such hags being found in Japanese myth alone.

History
An Ame Onna is a type of malicious yokai-hag from Japanese folklore that manifests as an ugly woman carrying a large sack, only ever appearing during rainstorms these gruesome spirits continually lick at rainwater from their hands like a wild animal and keep watch for children or infants, who they will abduct and spirit away using their sacks.