Donald Earl "Don" Messick(September 7, 1926 – October 24, 1997) was an American voice actor best known for his work for Hanna-Barbera, where he voiced such characters as Boo Boo Bear, Scooby-Doo, Papa Smurf, Dr. Benton Quest in Jonny Quest and Dick Dastardly's sidekick Muttley.
Messick had been involved in voice acting for half a century, keeping busy until 1996, when one day on set he remarked "I can't do this anymore" and ambled off the set. The following day, his agent released a statement that he had suffered a stroke on set and decided to retire. Although Messick had ended voice acting afterwards, he did make one final TV appearance as a guest on The Maury Povich Show being interviewed about his 50 years in voice acting. In 1997, a second stroke ended Don Messick's life.