Do you know ghouls from goblins and ghosts?
(German: "double goer"), in German folklore, a wraith or apparition of a living person, as distinguished from a ghost. The concept of the existence of a spirit double, an exact but usually invisible replica of every man, bird, or beast, is an ancient and widespread belief. To meet one's double is a sign that one's death is imminent. The doppelganger became a popular symbol of horror literature, and the theme took on considerable complexity. In The Double (1846), by Fyodor Dostoyevsky, for example, a poor clerk, Golyadkin, driven to madness by poverty and unrequited love, beholds his own wraith, who succeeds in everything at which Golyadkin has failed. Finally the wraith succeeds in disposing of his original. An earlier, well-known story of a doppelganger appears in the novel Die Elixiere des Teufels, 2 vol. (1815-16; "The Devil's Elixir"), by the German writer of fantastic tales E.T.A. Hoffmann