Spot is Eddie's loving pet dragon. He usually resides under the Munsters' staircase, but Eddie likes to play with him in the back yard at times, too. Spot, like any pet, occasionally has accidents. He's eaten the sofa, and tracked giant mud footprints into the living room. He also likes to chase cars, and sometimes he catches them. His expert sense of smell has caught bad guys, and found a lost Eddie. Spot likes to also bury things, such as people.
Spot is never completely shown, but we know he has scales. We only ever see his tail, and the outline of his face, usually breathing fire. He is skilled at games, and has beaten Herman at both checkers AND ping-pong.
According to Al Lewis, Spot was designed by Fred Gwynne and Al Lewis. According to Butch Patrick, Spot was the Tyrannosaurus rex model from the movie One Million B.C.