Wallace Michael Shawn is an American character actor, voice artist, comedian, playwright and essayist. His film roles have included those of Wally Shawn in the Louis Malle-directed drama My Dinner with Andre (1981), John Lahr in Prick Up Your Ears (1987), Vizzini in The Princess Bride (1987), Mr. James Hall in Clueless (1995) and the voice of Rex in the Toy Story franchise. He has appeared in a variety of television series, including recurring roles as Grand Nagus Zek in Star Trek: Deep Space Nine, Cyrus Rose in Gossip Girl (2008–2012), and Dr. John Sturgis in Young Sheldon.