Uncle Abner (left) visits Max's apartment.

Uncle Abner: "We better help [Max]. After all he is your sister's son."
Aunt Bertha: "My sister's son? I thought he was your sister's son."
Uncle Abner: "I don't think so. I hope not."
Relative of Maxwell Smart, married to Aunt Bertha.

If you're thinking of buying him a Christmas present, Uncle Abner's favored shoes are black Oxford 9C.

Portrayed by Charles Lane [Episode #12: "My Nephew the Spy"].