[ButterflyDemise]

I read about this monster recently: the Rokurokubi.

Definition stolen from here: A female monster with an extremely flexible neck. By day they are indistinguishable from normal women, but after nightfall rokurokubi stretch their necks out to any length in search of prey. According to one theory, they are seeking out men in order to suck the life energy out of them.

Or the story about Okiku~ (story also taken from the same link): She works as a maid at the home of the samurai Tessan Aoyama. One day while cleaning a collection of ten precious ceramic plates--a family treasure--she accidentally breaks one of them. The outraged Aoyama kills her and throws the corpse into an old well. Every night afterwards, Okiku's ghost rises from the well, counts slowly to nine and then breaks into heartrending sobs, over and over and over again, tormenting the samurai. Finally, vengeance is wrought when Aoyama goes insane. (In an alternate version, Aoyama wishes Okiku to become his mistress, and falsely accuses her of breaking a plate so that he can offer forgiveness in exchange for her love. When she refuses, he kills her.)

I thought it was pretty interesting and there's some things on other monsters and ghosts in that link~ I hope no one has posted it yet ;>>