Mittens is a tame gorilla that can perform sign language.
When Hayley is talked into eating meat for a day by Roger in "N.S.A. (No Snoops Allowed)", she confesses her wildest dream of eating a gorilla capable of sign language. Roger takes them to Gus Derwitt's Specialty Meats where they are set up with Mittens. But when the plates arrive, Hayley has reservations and Gus reveals himself to be a crooked fish and game warden. He shakes them down for their cash, which amounts to $60, two stamps and expired planetarium tickets, and turn them loose. After they're gone, he locates Mittens who is no longer as innocent as he appeared either, who takes his cut of the proceeds and bickers with Gus over the poor take, as Gus reminds him that he is the "husband" in their relationship.