Wallace Michael Shawn (born November 12, 1943) is an American actor, voice artist, comedian, playwright and essayist. His film roles have included those of Wally Shawn (a fictionalized version of himself) in the Louis Malle–directed drama "My Dinner with Andre" (1981), Vizzini in "The Princess Bride" (1987), Mr. James Hall in "Clueless" (1995) and the voice of Rex in the "Toy Story" franchise. He has also had roles in six of Woody Allen's films. His television work includes recurring roles as Jeff Engles in "The Cosby Show" (1987-1991), Grand Nagus Zek in "" (1993–1999), Cyrus Rose in "Gossip Girl" (2008–2012), and Dr. John Sturgis in "Young Sheldon" (2018–).