Invisible Movie Hint

This week's Invisible movie is a classic from 1976. The big clue in this screenshot is the meat carcasses hanging in the background that our hero is about to beat the heck out of with his fists. That should pretty much give it away.

As a bit of trivia, the movie was made for only $1.1 million and shot in just 28 days. But it ended up a hit earning over $117 million, and winning three Oscars, including Best Picture.

Simply identify the movie and turn it in with your first answer at Trivia for five bonus points.