The Creepy Backstory:
The clip is from Sydney Pollack's 1972 film Jeremiah Johnson, in which Redford plays the titular character. Johnson was a real guy back in the Old West, and his story is completely insane. Johnson's pregnant wife was murdered by the Crow tribe, spurring him to go on a two-decade revenge killing spree. If that wasn't disturbing enough, Johnson also ate his victims' livers, possibly because the Crow considered "the liver a sacred part of the body, necessary to enter the afterlife." And in real life he looked a tad less Redford-y.
Montana State Historical Society
Johnson was eventually captured by Blackfoot hunters, who were going to sell him off to the Crow. But he escaped, and after he killed one of the guards, he "chopped off his leg" and devoured it on the journey home. Maybe this GIF should be reserved for tweets in which people are agreeing on the sweet taste of human flesh.