The ultimate or penultimate round of an episode involved blindfolding the panel for a celebrity guest appearance (originally called "mystery challengers" by Daly) whom the panel had to identify by name, rather than occupation. (In the first episode, the mystery guest was New York Yankees shortstop Phil Rizzuto.) In the early years of the show, the questioning was the same as it was for regular contestants, but starting with the April 17, 1955 edition, panelists were only allowed one question at a time. Mystery guests usually came from the entertainment world, either stage, screen, television or sports. When mystery guests came from other walks of life or non-famous contestants whom the panel but not the studio audience might know, they were usually played as standard rounds. However, the panel might be blindfolded, or the contestant might sign in simply as "X," depending on whether they would be known by name or sight.