Der Januskopf (translated to English as The Head of Janus) was a silent German horror film released in 1920. It is one of three adaptions of the novel Dr. Jekyll and Mr. Hyde to be released that year, and the only of the 1920 adaptations to be considered lost. It was done without securing the rights to adapt the novel from the estate of Robert Lewis Stevenson. Directed by German cinema legend F. W. Murnau (who had some future success with unauthorized adaptions with the 1922 film Nosferatu). The film starred Comrad Veidt, who is well known for his role as Cesare in the horror film The Cabinet of Dr. Caligari and later starred as Gwynplaine in the 1928 film The Man Who Laughs. The film also featured horror legend Bela Lugosi (from Tod Browning's 1931 film Dracula) in a minor role. The cinematographer, Karl Freud, may also be a familiar name to some people, as he went on to direct The Mummy in 1932.
No footage from the film is believed to still be in existence, though there are a handful of surviving stills, which can be found online. The script also is believed to survive, but unlike the stills, it cannot be found on the Internet. It is believed to have used one of the first instances of a moving camera in cinema.
The film followed the novel very loosely. Instead of using a potion to transform, the doctor uses a cursed statue of the Roman god Janus. Also much like the film Nosferatu, the names were changed in hopes of avoiding getting caught infringing copyright. Dr. Jekyll for example was changed to Dr. Warren. Horror host Penny Dreadful XIII has stated that this is her most wanted lost horror film.