Around 6 p.m on Jan. 14, 1950, a second-year cadet at West Point named Richard Calvin Cox received a visit from a mysterious friend named George who had a German accent.

Shortly afterward, Cox left his dormitory and vanished. His disappearance is still unexplained; he’s the only cadet ever to go missing from West Point. After a fruitless investigation, he was declared legally dead in 1957.