S1·E61 Big Top Bungling

Heathcliff and Sonja go to the circus to see Heathcliff's cousin, Rollo the cat-clown. Rollo is troubled because the wild circus animals have become tame, the trapeze artists are afraid of heights, etc. Our hero discovers a plot by a rival circus, and with the help of the Catillac Cats, he fails the evil plan.