Empousa

Empusa is a demigoddess of Greek mythology. In later incarnations she appeared as a species of monsters commanded by Hecate

Empusa was the beautiful daughter of the goddess Hecate and the spirit Mormo. She feasted on blood by seducing men as they slept before drinking their blood Empusa is pictured as wearing brazen slippers and bearing flaming hair. By folk etymology, her name was said to mean "one-footed". This gave rise to the iconography of a one-legged hybrid, with a donkey's leg and a bronze prosthetic leg.

In later Greek mythology, her role was reduced to a species of Hecatean demon called an empuse or empusa The empuses were sent by Hecate to guard roads and devour travelers.According to Philostratus, empuses ran and hid, uttering a high-pitched scream, at the sound of insults. The empuses are best known for their appearance in Aristophanes's The Frogs, in which they scared Dionysus and Xanthias on their way to the underworld.

Today, the term is still used to refer to a shapeshifting hobgoblin said to pester Greek shepherds in the form of a dog, ox, or mule Empuses appear in the book "The Battle of the Labyrinth", part of the "Percy Jackson and the Olympians" series by Rick Riordan, and also in another series of books called the Cronus Chronicles wherein the name "Empusa" was used as an insult. In both stories, the empuse is a shape-changing, vampire-like creature that attempts to seduce a protagonist before its true form is revealed.