Tenacious D-The Pick Of Destiny - There Not Playing Their Guitars
This Slip-Up occurs whenever J.B. is dreaming of them having the Pick of Destiny. When J.B. starts off yelling he stops playing his part in the song (but you can still hear it). Then it zooms out for a second showing Kyle Gass, and he's not playing too! So Kyle is just standing there and J.B. is just yelling, and you can still hear them playing Guitars.
sometimes they have the song playing in the background as well as them looking like they are currently playing. they do that with the singing also. someimes during a song the person is singing and the next they are doing something else like running or fighting and you can still hear them singing but they arent moving their mouths to do so. its not at all a slipup.