What 1984 mockumentary follows a fictional heavy metal band?

The 1984 mockumentary about a fictional heavy metal band is This Is Spinal Tap.

Directed by Rob Reiner in his feature-film debut, the movie follows documentary filmmaker Martin “Marty” Di Bergi as he accompanies the English band Spinal Tap on an increasingly disastrous American tour. Christopher Guest, Michael McKean, and Harry Shearer play the band’s musicians, whose grandiose ambitions repeatedly collide with incompetence, bad luck, and interpersonal tension.

The film parodies rock documentaries and the mythology of arena bands. Its most famous gag involves guitarist Nigel Tufnel demonstrating that his amplifier’s volume knobs go beyond the usual maximum to “11,” creating the phrase “up to eleven.” Other running jokes include the band’s bizarre history of drummers dying in improbable circumstances and the infamous miniature Stonehenge stage prop.

Much of the dialogue was improvised from scene outlines, which gives the fictional documentary its naturalistic tone. The movie initially had only modest box-office success, but home video helped it become a cult favorite. The Library of Congress added it to the National Film Registry in 2002.