Claim: Leonid Kinskey (a Russain-German-American actor) played the roles of Prof. Hammershlag in My Favorite Martian (1964) and Prof. Overbeck in Batman's 1967 TV Series.
Evidence: Leonid Kinskey (c. 1894 or 18 April 1903 – 8 September 1998) was a Russian-German-American film and television actor who enjoyed a long career. Nov 1st 1964 My Favorite Martian Prof. Hammershlag Jan 4th 1967 Batman (TV Series) Professor Overbeck Jan 5th 1967 Batman (TV Series) Professor Overbeck