During the filming of the canoe scene, author James Dickey showed up inebriated and got into a bitter argument with producer-director John Boorman, who had rewritten Dickey’s script. They had a brief fistfight in which Boorman’s nose was broken and four of his teeth shattered. Dickey was thrown off the set, but no charges were filed against him. The two reconciled and became good friends, and Boorman gave Dickey a cameo role as the sheriff at the end of the film.

Wikipedia entry on Deliverance