Little Big Man

Little Big Man is an 1970 film directed by Arthur Penn. The screenplay is by Calder Willingham, based on a novel of the same name by Thomas Berger. It stars Dustin Hoffman as Jack Crabb, a 121-year-old survivor of the Battle of the Little Bighorn. But there's more to his life story than that: life as an adopted Cheyenne, a Snake Oil Salesman, an amateur gunslinger, and an attempt to go straight before he gets embroiled in the mad dreams of a general named Custer. Sometimes a parody of the Western genre, sometimes a Deconstruction.

The movie was named to the National Film Registry in 2014.

Tropes used in Little Big Man include:

Aren't You Going to Ravish Me?: In an early scene where the narrator/protagonist is first captured by the Cheyenne, his sister is shown worrying and complaining about what all these natives might be planning for her in the strange language they're speaking and saying "They're going to rape me for sure!" As time passes and nothing happens to her, however, we see that they're planning no such thing, and that she's actually getting rather annoyed because no one's paying very much attention to her at all.
Briar Patching: General Custer hires Jack Crabb as a scout, reasoning that because Crabb hates him and wishes to get revenge on him for killing the Cheyenne, everything he tells Custer will be a lie, thereby making him a "reverse barometer". This leads to a Crowning Moment of Awesome for Crabb when they get to the Little Bighorn and Custer asks if they should attack:

Crabb: General, you go down there.
Custer: You're advising me to go into the Coulee?
Crabb: Yes, sir.
Custer: There are no Indians there, I suppose.
Crabb: I didn't say that. There are thousands of Indians down there. And when they get done with you, there won't be nothing left but a greasy stain. This ain't the Washite River, General, and them ain't helpless women and children waiting for you. They're Cheyenne brave, and Sioux. You go down there, General, if you've got the nerve.
Custer: Still trying to outsmart me, aren't you, mule-skinner? You want me to think that you don't want me to go down there, but the subtle truth is you really don't want me to go down there!

Cruel Mercy: General Custer spares Jack Crabb's life, after Crabb attempts to kill him in his tent but loses his nerve at the last second. Crabb states in narration that this is the worst thing Custer could have done to him.
Disney Death: Played with. Cheyenne chief Old Lodge Skins, Jack's blind mentor, has finally grown tired of life. He and Jack ascend a hill where Old Lodge Skins prays for his death and lies down with his eyes closed. It then begins raining. Old Lodge Skin blinks, then sighs. "Sometimes the magic works. Sometimes it doesn't." and they both go back to their village.
Framing Device: Crabb in the hospital.
Hypocrite: Mrs. Pendrake, the wife of a fire-and-brimstone preacher, adopts Jack Crabb and tries to see to his moral and spiritual instruction. After he catches her having sex with a shopkeeper in town, he swears off religion for good and joins up with Snake Oil Salesman Mr. Merriweather. As Crabb puts it in his narration, "After Mrs. Pendrake, his honesty was downright refreshing."
I Owe You My Life: The life-saving action of the eponymous character just amplifies Younger Bear's hatred of him, though he cannot do anything till he repays the debt.

Younger Bear: I have saved your life. Now, the next time we meet, I can finally kill you without becoming an evil person. YAHOO!!

Me Love You Long Time: All the Indian women are played by Vietnamese women. And not a one but she's a giggling sex kitten eager to bed ~~Dustin Hoffman~~ Crabb.
Mighty Whitey: Averted. Crabb was adopted by the Cheyenne, but he was never their best warrior or their best leader. It could be argued that he was led by the events that unfolded around him, and could do little to change their outcome, being more an observer then anything else.
Nostalgic Narrator
Of the People: Crabb used the term "Human Being" when referring to "The People".
Sarcastic Confession: Crabb tells General Custer in the final battle scene exactly what's going to happen if he charges forward. He gives Custer the information because he knows that he won't be believed, and he isn't.
Snake Oil Salesman: Mr. Merriweather. Crabb also becomes one of these as his assistant.
Shout-Out: to any Western (including Three Godfathers) that uses the song "Shall We Gather At The River."
Soundtrack Dissonance: Towards the end when Custer's 7th Cavalry is massacring an entire Native American village, including the protagonist's family, in the background is the cheery strains of "Garry Owens" played by the regimental band. This was the actual marching song of the 7th cavalry.
Tar and Feathers: Happens to Crabb when he's found out as a Snake Oil Salesman.
Timeshifted Actor: While a child actor had to portray the 10-year-old Crabb, Dustin Hoffman wore make-up to portray the character's centenarian self. He made his voice sound old by going into his dressing room and screaming at the top of his lungs for an hour.
Unreliable Narrator: Crabb is quite likely one of these.