A daemonic ghost sent by Hecate[1] and appearing to the ill-fated.[2]
[Something] which seems to change into many forms. Aristophanes in Frogs [sc. indicates this]. [It is called] Empousa from the fact that it moves on one leg [heni podizein], i.e. that its other leg is bronze. Or because it used to appear from dark places to the initiated. She was also called Oinopole.[3]
But others say [sc. that it bore this name] because it changed form. It also seems to appear in the light of day, when they are offering sacrifices to the dead. Some say that she is the same as Hecate. But [another name for her is] Onokole, because she has a donkey's leg; which they call manure [βολίτινον ], that is donkey manure. For βόλιτος [is] the proper word for donkeys' excrement. Aristophanes in Frogs [says]: "by Zeus, I see a huge wild beast. -- What kind? -- Terrible. At any rate it's everything at once: first a cow, then a mule, then again a most beautiful woman. -- Where is she? I’m heading towards her. -- But she's no longer a woman, but a dog now. -- It is Empousa, then. -- At any rate the whole face is glowing with fire. -- And does she have a bronze leg?."[4]