The Algol eclipsing binary is in the constellation Perseus. It is sometimes called the Winking Demon Star because it varies dramatically in brightness and is the "eye" of the Gorgon, a creature slain by Perseus in mythology (also called the "eye of the Medusa" in Greek). The name Algol derives from the Arabic Ras al Ghul for the "demon's head"; the English word ghoul comes from the same root.