Zak (Zack Gottsagen), a Professional Wrestling-obsessed 22-year-old with Down syndrome, runs away from the retirement home where he lives so he can attend the wrestling school of his hero, the Salt Water Redneck (Thomas Haden Church). Along the way he befriends Tyler (Shia LaBeouf), a thief and fisherman who went on the run after destroying $12,000 worth of equipment. The two are pursued by Eleanor (Dakota Johnson), who cared for Zak at the nursing home, and the crabbers Duncan (John Hawkes) and Ratboy (Yelawolf), who want revenge on Tyler for destroying their property.
The Peanut Butter Falcon contains examples of:
- Ambiguous Ending: While Tyler is shown to survive his wounds, its unknown what comes next for the Trio in their drive to Florida.
- And Starring: Introducing Zack Gottsagen, with Jon Bernthal and Thomas Haden Church.
- Badass Boast: Zak gives his version of one to his opponent Samson one during their wrestling match.Zak: "You are not invited to my birthday party!"
- Big Friendly Dog: At one point Tyler hitchhikes with a man whose enormous dog spends the entire ride panting in Tyler's face.
- Blind Black Guy: Jasper, the man who baptized Zak.
- Casting Gag: Salt Water Redneck's friends Sam and Jacob are respectively played by actual wrestling icons Jake Roberts and Mick Foley.
- Chekhov's Gunman: The black friend of Duncan and Ratboy only appears in their introduction. He won't show up again until the climax in which he was an audience member in a wrestling event Zak participates in and proceeds to tell the two antagonists on Tyler's whereabouts.
- Chekhov's Skill:
- Tyler's misdirection skills are displayed when he lured Duncan and Ratboy away during a Chase Scene earlier in the film. He would use it again on Eleanor in a Kiss of Distraction mentioned below.
- One of the skills Tyler taught Zak is how to shoot. It comes in handy when he scares Duncan and Ratboy off when the two antagonists catches up to them the first time.
- Crowbar Combatant: Duncan hits Tyler with a crowbar in the film's climax.
- Curb-Stomp Battle: Zak's first opponent Samson isn't there to put on a show. After taking several hits without landing any of his own, Zak struggles to rise from the floor.
- Deep South: Where the movie is set.
- Deuteragonist: Tyler is the focus of the film after Zak.
- Disney Death: At first it seems that Tyler died from being assaulted with a crowbar by Duncan. But then the final shot shows him in the backseat of the car with bandages around his head as he, Eleanor, and Zak arrive in Florida.
- Dude, Where's My Respect?: Sam becomes envious of Zak's instant popularity with the crowd, feeling no one showed him any appreciation in his nearly four-decade career.
- Evil Laugh: Zak cackles while planning to be a heel.
- Family of Choice: Zak refers to Tyler and Eleanor as his family.
- Flipping the Bird: Eleanor gives one to Tyler during their first meeting. Later, Sam gives one to Zak For the Evulz.
- Gory Discretion Shot: The screen cuts just as Duncan hits Tyler with a crowbar.
- Green-Eyed Monster: Overlapping with Dude, Where's My Respect?, Sam stiffs Zak in their exhibition match out of envy for the crowd's adoration.
- Heroic Second Wind: Samson spends most of his wrestling match against the Peanut Butter Falcon (Zak) insulting and pushing him around for real instead of merely playing a heel for the crowd. When Zak's friends convinced him to really fight back he is able to get back up from Samson's abuse and toss him clear out of the ring.
- Hoist Hero over Head: Zak loves watching the Salt Water Redneck do the Atomic Throw, which involves lifting your opponent over your head and throwing him out of the ring. When he finally meets the Salt Water Redneck, Salt Water explains that the move was created with Camera Tricks. Zak still pulls it off during his match.
- Inspirationally Disadvantaged: The film is about a young man with Down Syndrome wanting to be a professional wrestler.
- Intergenerational Friendship: Zak gets along fine with his roommate in the nursing home, Carl.
- Karma Houdini: It is never revealed what happened to Duncan after he hits Tyler.
- Kiss of Distraction: Tyler kisses Eleanor while he handcuffs her to her steering wheel so she can't interfere with Zak's wrestling match.
- Manly Tears: Tyler starts crying when Zak tells him, "Tyler, I am going to give you all of my wishes for my birthday."
- Missed Him by That Much: Much of the second quarter of the film is Eleanor arriving on a place Zak and Tyler and meeting the people they've encountered.
- Mr. Fanservice: Tyler is frequently seen shirtless.
- Ms. Fanservice: Eleanor's legs are constantly on display, and she mostly wears a tight vest top that shows off her midriff. She also has a scene where she goes swimming with Zak and Tyler in her t-shirt and panties.
- Parental Abandonment: Zak lives in a retirement home because his family abandoned him and he had nowhere else to go.
- Privacy by Distraction: Tyler and Eleanor have Zak practice holding his breath underwater while they argue about him.
- Politically Incorrect Villain: Several antagonists have called Zak retarded.
- Posthumous Character: Mark, Tyler's older brother, is dead and only appears in flashbacks. While not shown, it's implied he died in a road accident due to Tyler falling asleep while driving.
- Protagonist Title: The Peanut Butter Falcon is the wrestling name Zak chooses for himself. In particular, it's based on the alias of his wrestling hero, Salt Water Redneck, as well as his love of peanut butter.
- Retired Badass: Clint, aka Salt Water Redneck, has long been retired from in-ring action, but after some prompting, is still happy to take long-time fan Zak under his wing and teach him what he knows.
- Ring Oldies: Sam is played by wrestling icon Jake Roberts, who was sixty four during the film's release. Likewise, Jacob is played by the similarly iconic Mick Foley, who was fifty four.
- Road Trip Plot: Most of the movie is spent with people driving, trekking or even in boat trips.
- Saw "Star Wars" Twenty-Seven Times: Zak watches his favorite wrestling videos over and over again. His roommate Carl complains, "I'd love to have a nickel for every goddamn time we've had to watch this tape. I'd be a rich 'un."
- Secret Handshake: Zak teaches one to Tyler.
- Shirtless Scene: Zak squeezes through the bars of his bedroom window in his underwear. Tyler removes his shirt everytime he's swimming.
- Spiteful Spit: Ratboy spits on Tyler after he and Duncan beat him up.
- Trademark Favorite Food: Peanut butter for Zak. He's seen eating it straight from the jar a few times, and — as a play on Salt Water Redneck's in-ring persona — forms the basis of his wrestling name.
- Training Montage: After Tyler agrees to be Zak's trainer, there's a montage of Tyler helping Zak work out and teaching him how to fire a gun.
- Took a Level in Badass: The film's main plot is for Zak learning how to be independent and skillful.
- Took a Level in Cheerfulness: Zak's innocence and optimism begins to rub on Tyler as the film progresses.
- Two Guys and a Girl: The film's main protagonists are Zak, Tyler and Eleanor.
- Vanity License Plate: The Salt Water Redneck's license plate says R3DN3CK.
- Vomit Discretion Shot: Zak gets seasick on Tyler's motorboat, but is obscured by the fabric he hides in.
- Would Hurt a Child: Tyler decks the boy who was bullying Zak to swim while repeatedly calling him a "retard". Given the circumstances mentioned, which would have gotten non-swimmer Zak killed for nothing but the bully's own sick amusement, he definitely had it coming.
- What Happened to the Mouse?: What happened to Duncan after he hits Tyler, is he imprisoned? Did Zak beat him up?
- Wounded Gazelle Gambit: Early in the movie, Zak persuades an old woman to pretend to choke on her pudding so he can make a break for it while the staff are distracted.
