Recently I came across a documentary from the early 1970's infiltrating and exposing some of the deviant practices of American Pentecostalism: Marjoe. Marjoe Gortner had been raised in Pentecostalism, and was himself a novelty within the movement being ordained as a preacher at four years old. As an adult in the early 1970's, Marjoe traveled the Pentecostal circuit with a film crew bent on exposing the movement. In the film, Gortner is accepted by a number of churches as a gifted preacher, none of which realized that he didn't believe a word of what he was preaching, nor did they realize the film crew was making a documentary to attack Pentecostalism. The documentary eventually won the 1972 Academy Award for Best Documentary Feature.
I found the film quite disturbing and even at times blasphemous. On the other hand, the film does capture some of the fraudulent practices of Pentecostalism. In understanding those people seeking to be caught up in a frenzied / emotional worship service, this movie is a valuable contribution.
I found the video below on the Internet Archive.