Harvey Muckenthaler is Stuart's fat next door neighbor and the main antagonist of some sketches.
The reason why Harvey can't stand Stuart is because he always annoys him.
Doreen appears to have somewhat of a crush on him until "Moving Day," in which Doreen kicks Harvey out of her house for insulting her and her son. This soon drives them to exact revenge by not moving after all.
He is portrayed by Paul Vogt.