Oscar Beregi Sr. (born Beregi Oszkár , 24 January 1876 – 18 October 1965) was a Hungarian film actor. He appeared in 27 films between 1916 and 1953. He is remembered for his performance as Dr. Baum in Das Testament des Dr. Mabuse . He began life in Budapest , Hungary and passed away in Hollywood, California . He had been the dad of actor Oscar Beregi Jr.