Tristram Coffin (1909-1990) was a character actor who often played gangsters. He appeared in various MSTied movies, and also played the titular character in the movie serial King of the Rocket Men. The costume of the main character of Rocket Men would later be used for the main character of Radar Men from the Moon, Commando Cody.
He was occasionally credited as "Tris Coffin".
- The Crawling Hand (Experiment #106) - as Chief Meidel
- Radar Secret Service (Experiment #520) - as Michael
- The Brute Man (Experiment #702) - as a police lieutenant and a radio announcer 
- Stamp Day for Superman (short, with RiffTrax Live MST3K Reunion Show) - as Principal Garwood
- Mr. Coffin is one of very few actors to appear in movies used in consecutive episodes of Mystery Science Theater 3000 (disregarding shorts/serials). See also Steve Franken and Grant Williams.