River of Fundament is a 2014 operatic experimental film written and directed by American contemporary artist and filmmaker Matthew Barney, and co-directed by longtime collaborator Jonathan Bepler.

It was produced by Barney and the Laurenz Foundation, and is loosely based on American author Norman Mailer's 1983 novel Ancient Evenings.

The film features Barney, Dave Bald Eagle, Milford Graves, John Buffalo Mailer, Ellen Burstyn, Maggie Gyllenhaal, Madyn Greer Coakley, Paul Giamatti, Shara Nova, Joan La Barbara, Elaine Stritch, Debbie Harry and Aimee Mullins.

With each reincarnation, he wakes up in a river of feces running beneath his Brooklyn Heights apartment, where a funeral gathering is also being hosted.

[1] Hathfertiti is variously portrayed by Ellen Burstyn, Maggie Gyllenhaal, and Madyn Greer Coakley at different stages of her life.