Dane with spots and buck teeth is Scooby-Doo 's slow-witted cousin . Dum lives with Ma and Pa Skillet, in the Okefenokee swamp of southern Georgia . Whenever Doo and Dum greet each other, Scooby-Doo yells, "Scooby-Dum" and Scooby-Dum says, "Scooby, doobie, doo." They then do a special handshake involving two