From the 1970 teensploitation film Musical Mutiny, directed by Barry Mahon.
"A ghost of a Caribbean pirate rises from his resting-place to visit his old haunt. Finding it covered by an amusement park, and seeing that Iron Butterfly is giving a concert, he decides to liven things up by opening the gates and letting screaming fans in for free. Iron Butterfly gets upset because this means they won't get paid and they storm off the stage forcing park officials to bring on local bands such as Grit, New Society, and the Fantasy to come up and play. Fortunately, a wealthy flower child offers to pay Iron Butterfly if they finish their concert. Iron Butterfly accept and settle down to play their epic hit "In-a-Gadda-Da-Vida" and several other songs." (Synopsis courtesy of The Video Beat)
Posted by FeitenFan.