original Star Trek , Kang is a Klingon , and Kodos ("The Executioner") is a human villain. Barney Gumble (Homer's drinking buddy) – Barney Rubble from The Flintstones . Troy McClure (actor) – B-movie actors Troy Donohue and Doug McClure. Dr. Nick Riviera (enterprising physician) – Elvis Presley 's physician, George C. Nichopoulos, was called