Grandpa vs. Grandpa / The Big Game Hunter

A convict named Jackknife Jake escapes from prison and is looking for a place to hide. Surprisingly, he's a dead ringer for Grandpa Nutmeg. Heathcliff and Iggy sees the report about the convict on TV and thinks it's Grandpa and tries to hide him. Jake sneaks into the house and dresses like Grandpa and soon is discovered by Heathcliff and Iggy, but they become confused about which is the real Grandpa.
Hoping to score some free food, The Catillac Cats meet Sidney and Sir Perciful Slimeford, a big game hunter who sets his sights on capturing Riff Raff after he ruins his award ceremony.
This is season 1, episode 58.