lamia

noun1

1. •
   A monster preying upon human beings, who sucked the blood of children, often described as having the head and breasts of a woman and the lower half of a serpent.

   • Apollonius […] by some probable conjectures, found her out to be a serpent, a lamia, and that all her furniture was like Tantalus' gold described by Homer, no substance, but mere illusions. — 1624