Sketchbook - Tako nyōbō in the bath (NSFW) (Patreon)

A man from Kanazawa was astonished by how good the broth that his wife made for him every day tasted. The broth was so delicious, in fact, that he began to grow suspicious of her. One day, he pretended to head off to work but instead climbed up into the rafters to spy upon his wife. He watched as his wife took out a large washbasin and filled it with boiling water. Then, she transformed into an octopus and entered the tub. She splashed about inside the boiling tub. His wife was using her own body as soup stock!

The man climbed down from the rafters and confronted his wife. “This whole time you’ve been washing your body like this and feeding me your bathwater?!”

The wife replied, “That’s right. And now I’m done.” After that she disappeared and was never seen again (link).