'Little Big Man' (1970)
We first see Hoffman buried under latex prosthetic make-up, portraying the 121-year-old Jack Crabb near the end of his life (the actor allegedly spent hours screaming in order to get the right worn-out tone of an impossibly geriatric man); over the next two-plus hours, viewers watched as he also played this frontier Candide as a teenager, an adult, a product of both white and Native American civilizations, a warrior, a pacifist, a perpetrator of manifest-destiny shenanigans and a victim of them. It's an astounding run through the stages of both a man's life and our nation's Western-era history, as Hoffman humanizes Arthur Penn's attempt to draw parallels between Indian massacres and our then-current imperialistic mishaps abroad. Film historian David Thomson noted that the role works partially because Hoffman was "riding the picaresque adventures of a put-upon outcast all the better because of his own denial of starriness." The actor himself put it more bluntly in an interview right before the film's release: "You have to be willing to be ugly."