Finn and Jake follow a Sea Lard, and in doing so, are led to a strange new world.
Tropes:
- Aardvark Trunks: The alternate form of Tree Trunks the elephant is Bush Roots the anteater, who looks pretty much like an elephant with smaller ears and a bushy tail.
- Alternate Self: Finn, Jake, Bubblegum, Marceline, BMO, Choose Goose, Tree Trunks, Mr. Pig, Mr. Fox and Lady all have alternate counterparts in the grotto world.
- Alternate Universe Reed Richards Is Awesome: Unlike the short and squat regular Mr. Pig, the alternate Mr. Pig is not only anthropomorphic, but tall and buff.
- And You Were There: Jake tells Ice King about all the lookalikes they saw, including Ice King's double "Princess Purple Patch".
- Animation Bump: The animation becomes more fluid after Finn and Jake go through the whirlpool.
- Art Shift: The world beyond the whirlpool is drawn in a slightly different style with Line Boil and fuller animation. Finn notes that it's "familiar, but weird."
- Butt-Monkey: Finn assumes the reason the Sea Lard wandered off in the first place was because it didn't feel appreciated. In the world beneath the water nymphs' grotto it's very highly valued — as a rolling pin.
- Continuity Nod: Finn reveals he really does think Shelby the worm is a nerd, though he's annoyed Shelby turns out to be wrong about Sea Lards (they're mammals not fish).
Finn: I can't believe I just believe Shelby 'cause he's a nerd.
Jake: I know. It's in his tone.
- Cordon Bleugh Chef: The water nymphs invite Finn and Jake for hotdogs which are apparently made out of frogs; one of them stores the finished "wieners" in her hair.
- Creepy Children Singing: The water nymphs sing a song about crushing frogs that echoes creepily throughout the cavern.
- Down the Rabbit Hole: Actually happens twice. First when Finn and Jake enter the grotto at the bottom of the pond, then when they go through the whirlpool inside the grotto.
- Follow the White Rabbit: Finn and Jake go after the Sea Lard, leading it to a new world at the bottom of their pond.
- While Finn and Jake never see them, Finn's counterpart is a white rabbit-boy, and Jake's is a seal-like creature.
- Forgetful Jones: Ice King lampshades his poor memory.
Finn: But Simon, if you go there (to the grotto) you'll lose your memories.
Ice King: What memories? I'm like a goldfish over here.
Jake: In what way exactly?
Ice King: Hm? Oh, hey Jake. ...Where am I?
- G-Rated Drug: It's implied "Princess Purple Patch" is addicted to the purple stuff.
- Intoxication Ensues: Touching the purple stuff turns out to make people dopey and absent-minded.
- Lotus-Eater Machine: The water nymphs warn Finn and Jake not to touch the purple stuff. When they do, they lose their memories.
- Mythology Gag: Jake's "You are crazy, you are so crazy!" to Lady's grotto counterpart is a reference to the pilot, where he says the same thing to the Rainicorn.
- Silly Walk: After Finn and Jake get high on the purple stuff, their way of walking becomes very silly and floppy.
- Shout-Out:
- Touch fuzzy, get dizzy: The purple stuff turns out to be fluff-balls that make Finn and Jake very "drunk".
- "Princess Purple Patch" and "Pond Princess Bubblegum" look a bit like a Jynx and a Ditto, respectively.
- An unused title card concept for this episode is based on the iconic final shot of End of Evangelion, putting Finn and Jake in place of Shinji and Asuka, and replacing the giant Lillith head with the Sea Lard.
- Stealth Pun: BMO's grotto counterpart is a bee. Bee-MO.
- True Art Is Angsty: invoked "Flower-Marceline" sings a very sad song about not wanting to be in her body but she assures Finn and Jake she just likes making sad songs.
- Vocal Dissonance: "Princess Purple Patch" is a female alternate version of Ice King, but talks with his gravelly masculine voice.
