Heathcliff and the Catillac Cats

Heathcliff's Double [Heathcliff] (1x57)

Air date: Oct 25, 1984

A mild-mannered cat named Henry -- who looks exactly like Heathcliff -- wanders into the neighborhood. When Spike thinks he has beaten up Heathcliff, Heathcliff catches on and joins forces with Henry to make Spike look like a fool.