Claim: Leonid Kinskey (a Russain-German-American actor) played the roles of Prof. Hammershlag in My Favorite Martian (1964) and Prof. Overbeck in Danger Man's 1967 TV Series.
Evidence: Professor Overbeck Batman (TV Series) Jan 4th 1967 Professor Overbeck Batman (TV Series) Jan 5th 1967