Ame-onna

Ame onna (Japanese: 雨女 or あめおんな, meaning "rain woman") are a class of yokai that appear on rainy days and nights. They summon rain wherever they go, and are often blamed for kidnapping and spiriting children away.

Myths & Legends
Ame onna are related to minor rain deities. However, unlike the gods, ame-onna are not benevolent. Though the rains they bring might save a village in drought or bring fortune to farmers, ame-onna have another purpose in mind: they wander the villages on rainy nights looking for newborn babies. If they should find a child born that night, they snatch it and carry it off into the darkness, spiriting it away to turn it into another ame-onna.

Mothers who have their babies snatched away in this manner are sometimes known to transform into ame-onna themselves out of grief and despair. Having lost their minds, these transformed women roam the streets at night with large sacks, hoping to replace what was stolen from them while they were still human. They sneak into houses where crying children can be heard, and steal them away from their homes into the night.

Appearance
They appear as depraved, haggish women, soaked with rainwater, often licking the rain off of their hands and arms like wild animals.

Origin
The first ame-onna go back to the ancient folk religions of Japan and China, where the rains were said to be brought by benevolent gods and goddesses who live as clouds by morning and as rain by night, forever traveling between Heaven and Earth. Legend has it that somehow, some of these rain-bringing goddesses became corrupted and gradually evolved into evil yokai, abandoning their divinity to live among mortals and prey upon them.