Tropes
- Ambiguously Evil: This episode establishes Peppermint Butler as this. Just mentioning his name will get Death himself to do anything you ask. Also, he threatens to steal Finn and Jake's flesh in their sleep at the end, and it's unclear if he's joking or not, or what he could possibly use it for.
- Big Stupid Doo Doo Head: Death says that Finn can't hurt him with his kicks because "your brain is stupid." Finn retorts "YOUR brain is stupid!".
- Blunt "Yes":Death: Okay... who do you think won?
Jake: Aw, man! Skeleton guy by a landslide! He was all like... (does death metal growl)!
Finn: DUDE!
Jake: What? Skeleton guy was awesome! You want me to lie?
Finn: Yes... - Brick Joke: Princess Bubblegum says she will return "on the morrow" after her conference before summoning a giant bird to ride on. Later, Finn believes he and Jake have plenty of time to fix their mistake because she would be back "on the morrow", which is another way of saying "tomorrow". Unfortunately, Jake clarifies that the morrow is the same bird that Bubblegum used and would be back sooner than they anticipated.Jake: Are you listening, man? THE MORROW... IS... A... BIIIIRD!
Morrow: SKREEEEEE! - Chess with Death: Finn must face Death in a musical contest in order to get the soul of the Princess Plant and get Jake's memories back. Death wins easily thanks to backing his death-metal growling with magical pyrotechnics.
- Cool Old Guy: Death turns out to be a rather rocking dude.
- Foot Popping: Jake does this when Death kisses him to give him back his memory.
- The Grim Reaper: Death is the messenger and ruler of the dead.
- It Amused Me: Immediately after Finn warns Jake that they'll have to be quiet to sneak past some skeletons, Jake farts loudly. His only excuse is "I thought it would be funny!"
- Literal Metaphor: Jake explains that when Bubblegum said she'd "return on the morrow", she was refering to her pet bird.
- Pals with Jesus: Finn and Jake are saved because Death is buddies with Peppermint Butler.
- Poor Communication Kills: When Bubblegum said she would return "on the morrow", Finn thought she meant as in "tomorrow". As Jake explains, "the Morrow" is the name of her "crazy-fast" Giant Flyer steed, meaning Finn and Jake have a lot less time than Finn thought to retrieve the soul of the Princess Plant.
- Reverse Psychology: A talking skull tries to trick Jake into drinking from the River of Forgetfulness. Finn tells him not to listen to the skull, who changes tack by telling Jake "Don't drink the water," and Jake immediately falls for it.
- Rescued from the Underworld: The basic plot of the episode is Finn and Jake having to journey to the underworld to rescue the soul of Princess Bubblegum's favorite flower.
- Shout-Out: The River of Forgetfulness in the Land of the Dead is an obvious reference to the River Lethe of Classical Mythology.
- That Poor Plant: Finn and Jake have some rather questionable ideas of how to care for Bubblegum's Princess Plant, and end up killing it.
