Mr. Grumper (The Spirits of '76)

"Grumpy old grumper" is the nickname Shaggy Rogers gave to a security guard (whose real name he never learned) at the Splitsonian Institute.

The Scooby-Doo Show
Shaggy thought he was a good suspect to be one of the traitor ghosts they saw at the Institute, but he turned out to be innocent.

Appearances

 * The Scooby-Doo Show
 * The Spirits of '76