Hercules and the Griffin

Hercules and the Griffin is an episode of Hercules: The Animated Series. It aired on November 20, 1998.

Summary
Hercules and his class visits an old age home, where they're each assigned a senior citizen to befriend. In an effort to connect with his oldster, a gruff old griffin named Griff (Tim Conway), Hercules accidentally reveals the treasured diamond that the Griffin had been guarding for decades from Arismap (Harvey Korman) the King of the Arismapse (thieving mountain gnomes) who plans his latest attempt to steal it.