The Special doesn't seem all that special--what, surprise luncheon meat grilled with some mustard and maybe cheese? But damn is it good, and the hand-mixed soda with it. It's small and not very filling, though, true to the name of the restaurant. Munch on one of those little Slim Jim-lookin' things too, while you're at it.
Mustard-haters, don't worry about the strict requirement that the mustard goes in your sandwich. They don't put in enough to clear the sinuses of a baby hamster.