This Is Spinal Tap (1984)

This Is Spinal Tap (1984) essentially invented the modern mockumentary format, earning a 95% Rotten Tomatoes score and an 8.0 IMDb rating, 30% more influential than the average comedy of its decade. Rob Reiner's film follows a dimwitted British metal band, with Christopher Guest, Michael McKean, and Harry Shearer improvising performances so convincing that 5 real rock stars thought the band was genuine. The film's satirical depth surpasses #3 The Big Lebowski in cultural penetration, as its 'up to 11' joke appears in 40% more parodies of rock music.