Wallace Michael Shawn is an American actor, playwright, and essayist. His film roles include Wally Shawn (a fictionalized version of himself) in 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 (1995–2019). He has also had roles in six of Woody Allen's films. His television work includes recurring roles as Jeff Engels in The Cosby Show (1987–1991), Grand Nagus Zek in Star Trek: Deep Space Nine (1993–1999), Cyrus Rose in Gossip Girl (2008–2012), and Dr. John Sturgis in Young Sheldon (2018–present). His plays include the Obie Award–winning Aunt Dan and Lemon (1985), The Designated Mourner (1996) and Grasses of a Thousand Colors (2008). He also co-wrote the screenplay for My Dinner with Andre with Andre Gregory, and scripted A Master Builder (2013), a film adaptation of the play by Henrik Ibsen, in which he also starred. Haymarket Books published his books Essays (2009) and Night Thoughts (2017).