Related Clues:

• Opening in "Hollywood Squares," essentially
• "___-Tac-Dough" (quiz show)
• First X, potentially
• Involuntary jerk
• ___ Tac (breath freshener)
• "Twitch," minus every other letter
• Tic or twinge
• Nervous twinge
• First O, maybe
• Tic, e.g.
• Sudden cramp
• Opening in "Hollywood Squares"
• Involuntary muscle movement
• Contraction of a sort
• First X or O, say