In classical mythology, the Cap of Invisibility (Ἅϊδος κυνέη (H)aïdos kyneē in Greek, lit. dog-skin of Hades) is a helmet or cap that can turn the wearer invisible,[1] also known as the Cap of Hades or Helm of Hades.[2] Wearers of the cap in Greek myths include Athena, the goddess of wisdom, the messenger god Hermes, and the hero Perseus. Those wearing the Cap become invisible to other supernatural entities, akin to a cloud of mist sometimes used to remain undetectable.[3]