Jorōgumo (絡新婦), the spider-woman in Yōkai folklore, is a predatory ghost found in Japanese folklore. There are spider creatures that shape-shift into beautiful women, often seducing their victims and devouring them.
There are cases of Jorōgumo appearing as full grown women and approaching samurai with claims of children that belong to the men. But there is a very interesting story of a Jorōgumo who stays spider size and infects the dreams of a man named Magoroku. There are cases of Jorōgumo living near waterfalls and strangling the men or dragging them down to the water.
The spider as seductress is not only in Japan, we find cases of this also in other world folklore as well. Creepy!