Heathcliff! Based on the comic strip by George Gallagher. I used to love the comic strip, and when the cartoon came out, I was instantly hooked. Heathcliff was like a naughtier Garfield, with more energy. I used to try to get home from school in time to watch it, I believe it aired on WGN. The animation was great, I believe it was done by Japanese animators. And I think it was the same people who worked on Inspector Gadget.