Crystal appeared briefly in the Rob Reiner "rockumentary" "This Is Spinal Tap" (1984) as Morty The Mime, a waiter dressed as a mime at one of Spinal Tap's parties. He shared the scene with a then-unknown, non-speaking Dana Carvey, stating famously that "Mime is money." He later starred in the action comedy "Running Scared" (1986) and was directed by Reiner again in "The Princess Bride" (1987), in a comedic supporting role as "Miracle Max". Reiner got Crystal to accept the part by saying, "How would you like to play Mel Brooks?" Reiner also allowed Crystal to ad-lib, and his parting shot, "Have fun storming the castle!" is a frequently-quoted line.