1x17 - Heathcliff and the Catillac Cats

Spike's cousin, Bull, is a ferocious looking guard dog who sports a bone out of his mouth the way a tough guy might use a cigar. He convinces Spike that he no longer should take guff from Heathcliff and proceeds to teach him to defend himself but to no avail. After Bull has harassed everyone in the neighborhood, he challenges Heathcliff to a fight in the vacant lot on Elm Street and guess who wins? Who else, Heathcliff!