In folklore, a will-o'-the-wisp, will-o'-wisp or ignis fatuus (, plural ignes fatui), is an atmospheric ghost light seen by travelers at night, especially over bogs, swamps or marshes. The phenomenon is known in English folk belief, English folklore and much of European folklore by a variety of names, including jack-o'-lantern, friar's lantern, hinkypunk and hobby lantern and is said to mislead travelers by resembling a flickering lamp or lantern. In literature, will-o'-the-wisp metaphorically refers to a hope or goal that leads one on but is impossible to reach or something one finds sinister and confounding.