For all the success of the Hanna-Barbera stalwarts in the 1960s ("The Flintstones", "The Jetsons", "Scooby-Doo, Where Are You?"), the studio actually succeeded most in its sheer variety and breadth. Many of its series lasted only one or two seasons, and even those half-hour shows were usually split between one set of characters and another (or three or four at times.)
Characters such as Quick Draw McGraw and Wally Gator shared screen time with lesser luminaries like Snooper & Blabber and Augie Doggie. These backups were often testing grounds for characters - successful ones like Peter Potamus ended up with their own shows, while most of them simply faded into obscurity. Such is the tale of "Punkin Puss and Mushmouse" which ran as the B-side for 13 episodes during the initial season of "Magilla Gorilla", debuting on January 14, 1964.
Mushmouse (voiced by H-B veteran and the infamous Gopher from "Winnie the Pooh", Howard Morris) and Punkin Puss (the venerable Allan Melvin, who also gave life to Magilla Gorilla) shared a house in an unnamed location, presumably in the Ozarks. Together, these two hillbilly animals co-existed on an uneasy balance. For a cat and mouse (Hanna-Barbera's specialty), they spent very little time actively trying to get the best of each other. Instead they would often be pitted against each other in an attempt to be the first to take advantage of some get-rich-quick scheme or similar competition. In the end, neither one would end up winning, and a fight would ensue between the two.
Most of the gags seemed to involve the "hillbilly feud" aspect of things, maybe taking advantage of shows like The Beverly Hillbillies' newfound popularity. However, as previously stated, they were merely a backup to the real star of the series, Magilla. They were replaced in the middle of their 1965 season by Ricochet Rabbit, and only made three more sporadic appearances in 1966. All told, 25 episodes were made, but only 24 made it to air (the pilot never saw the light of day.) The last one, "Misfortune Cookie", aired January 24, 1966.
You can catch reruns of Punkin Puss and Mushmouse on the Boomerang network, but don't expect to see the post-1964 episodes: they never seem to come on. Another sad but true story on the fate of the forgotten cartoons.