Fern finally has his fatal mental breakdown, and sets out to replace Finn.
Tropes:
- Accidental Murder: Finn didn't want to kill Fern; his robotic arm mistook him saying "finality" for "fatality" and put the weed-whacker function into overdrive.
- Bare-Handed Puppetry: In the introduction video for the mechanical arm, Princess Bubblegum amuses Finn with a puppet.
- Beat: After Finn tells Fern he's like a brother, or maybe even closer, Fern stares at him for a good long while before telling him to walk into the trap.
- Brick Joke: Jake goes to buy a new vuvuzela because BMO broke his old one. When Finn comes back, you can see BMO trying to break Jake's new vuvuzela.
- Call-Back: The prison Fern traps Finn in is a near-replica of the inside of the Finn sword.
- The fight scene mirrors the creation of the creation of the Finn Sword, the way Finn sneaks up on Fern while screaming and "kills" him. Doubles as foreshadowing for Fern surviving the attack, and metaphorically becoming Gumbald's sword.
- Dissonant Serenity: BMO cheerfully replies that he guessed that Finn killed Fern.
- Don't Make Me Destroy You: Finn really doesn't want to kill Fern, but since Fern is beyond hope he has no choice.
- Downer Ending: Fern undergoes a Face–Heel Turn and almost immediately pays dearly for it, while Finn has a Heroic BSoD over destroying most of Fern by accident.
- Face–Heel Turn: Fern, stewing over his recent failures, decides There Can Be Only One and turns on Finn.
- Foreshadowing: The fight scene mirrors the creation of the creation of the Finn Sword from "Is That You?", foreshadowing Fern surviving the attack, and metaphorically becoming Gumbald's sword.
- Good Eyes, Evil Eyes: Fern gets the same eyes as the Grass Sword curse creature after he decides to replace Finn.
- I Am Spartacus: After BMO confesses to breaking Jake's vuvuzela, NEPTR also claims he broke it, possibly for attention. Fern (while pretending to be Finn) quickly joins in.
- Justified Title: The title refers to the bucket of trash in Fern's prison, the bucket in Finn's backpack, and the bucket the mysterious figure used to collect Fern's remains.
- Kill and Replace: Fern decides to replace Finn, though instead of killing him he wanted to secretly keep him prisoner. However, Fern is such in inept jailer that Finn would have likely starved to death if he hadn't managed to escape.
- My God, What Have I Done?: Finn after he accidentally kills Fern.
- New Powers as the Plot Demands: Justified, Finn's prosthetic arm has dozens of different attachments. Finn just never noticed because there was ketchup on the microphone. And because, well, he's Finn.
- Rock–Paper–Scissors: Finn and Fern play it on their way to the ruins. Fern is upset that they keep tying, but he gets even more upset when he loses.
- Sequel Hook: Fern's sentient remains are picked up by some mysterious figure, later confirmed to be Princess Bubblegum's Great-Uncle Gumbald.
- Thousand-Yard Stare: Finn doesn't come out of killing Fern well.
- Twin Switch: Using his newfound Shapeshifter abilities, Fern is able to pass himself off as Finn. The first time was a joke between him and Finn, but then it turns serious when Fern traps Finn so he can take over his life.
- Wham Episode: Finn kills Fern (accidentally), a sentient being whom Finn really cared for.
