Medusa is a roaming monster from Kings Quest III: To Heir is Human, based loosely on the gorgon of Greek myth she stalks the desert and attempts to turn Gwydion to stone: however he uses a mirror to turn the evil creature to stone before she can succeed in her malicious deed.

When encountering Medusa it is important for the player to face Gwydion away from her as soon as she appears on the screen, otherwise her dreadful stare will turn him to stone - the player must also quickly type "show mirror to Medusa" before she touches Gwydion as her touch is also capable of turning the hero to stone.