In the later years of TV show, writers often try to boost ratings by tossing in extra characters, often with little or no pretext. (Did they think we wouldn't notice little Oliver sitting at the breakfast table along w...ith the other Bradys?) No producers are more guilty of this than cartoon giants Hanna & Barbera.
It seems that they couldn't resist throwing in a new (often supernatural) character into most every show. To Scooby Doo, they added the ever-hyper Scrappy Doo. To the Jetsons, they added a new springy-legged pet, Orbity. To Josie and the Pussycats, they added an alien, Bleep.
My personal favorite is the floating green alien they added to The Flintstones that only Fred and Barney could see. What was its name?