Azuki babā

Azuki babā or Azukitogi babā (Japanese: 小豆婆 or あずきばばあ, meaning "bean hag" or "bean grinding hag") is a yokai in the form of an old woman dressed all in white, singing in a husky, ugly voice as she washes beans

Myths & Legends
the people of Miyagi prefecture tell of a much more sinister member of the azuki family of yokai. Rather than the benign and cute azuki arai known throughout most of the country, this northeastern variation takes the form of a fearsome old hag.

Azuki babā only appears at twilight – particularly on rainy or misty autumn nights. Their song is similar to the azuki arai’s, except that azuki babā usually follow through on the threat to catch and eat humans.

Witnesses of azuki babā who have survived to tell their experience describe and eerie white glow visible through the thick white mist. From the mist, the husky voice of an old hag can be heard singing her ghastly song and counting beans as she washes them in the river with a strainer. Those who don’t turn back at this point never make it back.

Origin
Despite their ferociousness, azuki babā are much more rare than their harmless bean-washing counterparts, and are usually just used as stories to scare children into behaving properly. Of all the variations of azuki-related yokai, this one is the most likely to actually be a shapeshifted an evil itachi, tanuki, or kitsune, imitating the harmless azuki arai in order to attract a curious child to catch and eat.