Empusa

Empousa (Έμπουσα, Empousā, of unknown meaning ) is a demigoddess of Greek mythology. In later incarnations she appeared as a species of monsters commanded by Hecate (known in English as an empuse).

She is often associated or grouped with the demigoddesses Lamia and Mormo, who were likewise related as a kind of spectres in later mythology (the lamias and mormolyceas, respectively).

As a demigoddess
Empousa 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 (much like a female vampire; see sleep paralysis). Empousa is pictured as wearing brazen slippers and bearing flaming hair. By folk etymology, her name was said to mean "one-footed" (from Greek *έμπούς, *empous: en-, one + pous, foot). This gave rise to the iconography of a one-legged hybrid, with a donkey's leg and a bronze prosthetic leg.

Later and modern usage
In later Greek mythology, her role was reduced to a species of Hecatea spectre called an empuse or empusa (pl. empusae). The empuses were sent by Hecate to guard roads and devour travelers (Hecate was also the goddess of roadsides). 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. Empusa is a main antagonist turned heroine in the novel Grecian Rune by James Matthew Byers.

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 (perhaps harkening back to the classical representation).