The High Sign (1920)
Buster unwittingly is initiated into a secret society of assassins where he takes a bloody oath with his hand on a skull, and is given the secret knock and hand sign.
The 'High Sign' (1920). Directed by Edward F. Cline, Buster Keaton, written by "Buster" Keaton, Eddie Cline. "Buster" Keaton, Bartine Burkett, Charles Dorety, Ingram B. Pickett, Al St. John. USA, English (intertitles), 21 min, Silent, Black and White.