- Sheldon J. Plankton
- Karen Plankton
- Squidward Tentacles
- Mr. Stinky (debut)
- Cat (mentioned)
- SpongeBob SquarePants
- Eugene H. Krabs
- HAZMAT Unit
- Fire fish
- French Narrator
- Gary the Snail
- Shelley (2 cameos)
- SpongeBob's grandson (indirectly mentioned)
At the Chum Bucket, Plankton is on a wagon preparing for another attempt to steal the Krabby Patty secret formula. He is pushed into the Krusty Krab and reveals from underneath the blanket covering the wagon a skunk (which he named Mr. Stinky) to everyone there. The customers think the skunk to be just a cat, but Plankton sets Stinky off by scaring him with a bee. All of the customers, Squidward, SpongeBob, and Mr. Krabs frantically leave the Krusty Krab due to the stink. Mr. Krabs knows that Plankton is in the Krusty Krab alone and takes one of SpongeBob's arms to use as a nose plug and heads inside. Mr. Krabs heads into his office to find that Plankton surrounded the safe with dynamite. Unfortunately for Plankton, the safe has another safe inside and Mr. Krabs crushes Plankton with his fist, and he is tossed out of the window by SpongeBob. Mr. Stinky is removed from the restaurant by the HAZMAT Unit and sent away back up to the surface in a basket lifted up by balloons, only for the little number of balloons to bring him back down toward Bikini Bottom, causing the people to run away. Mr. Krabs, worried something like that will happen again, wants SpongeBob to take the secret formula home with him while he makes adjustments to his safe. However, the two of them did not know Plankton was listening to everything with his severed antenna.
Later at closing time, SpongeBob tries to sneak home with the formula, but is greeted by Plankton. The two of them talk for a little bit until SpongeBob excuses himself to go home. The next morning, SpongeBob is seen talking to Gary entrusting the safety of the secret formula to him. Plankton is spying on them and watches as SpongeBob leaves. Plankton then disguises himself as a door-to-door salesman selling snail products. However, Gary closes the door on him and Plankton angrily walks off. Moments later, Plankton is disguised as a Sweetie Patrol Girl and tries to sell cookies to Gary, but Gary ends up putting the sofa with Plankton on it outside. Plankton throws down the cookies in a fit of anger and gets blown up as a result, making a mental note that nitroglycerin is not a good substitute for vanilla extract.
Plankton finally manages to get inside SpongeBob's house by distracting Gary with a fake cut-out of himself. Plankton searches through SpongeBob's house tearing up everything in sight until he is confronted by Gary. Gary manages to beat up Plankton until Plankton escapes through Gary's shell thinking the secret formula is inside. Gary's eyeball starts to chase Plankton throughout his shell. SpongeBob eventually comes home and is horrified by the condition of his house. However, he is glad that the secret formula is safe (which was on top of his television the entire time). SpongeBob notices something is wrong with Gary and decides to take him to the vet. Back inside Gary's shell, Plankton makes it to the center of the shell and appears to have gotten the secret formula. However, it turns out that Plankton was hallucinating the entire time due to the fumes from Gary's shell and runs off into the sunset with what he believes to be the formula (which was actually one of SpongeBob's old grocery lists), as the episode ends.
|( ‣ ) Production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
• Earl's Revenge - Sage Guyton, Jeremy Wakefield [Title card]
‣ Stool Pigeon - Kenny Graham [Plankton going to the Krusty Krab.]
‣ Circus Parade (B) - Dick Walter [Skunk revealed.]
• Vibe Q Sting - Nicolas Carr [Customers crowd around the skunk.]
• Light Suspense Segway - Nicolas Carr ["Gather in real close."]
‣ Dramatic Cue (E) - Ronald Hanmer ["Time to trigger the stench!"]
• Sponge Monger - Sage Guyton, Jeremy Wakefield [The Krusty Krab is filled with skunk odor.]
‣ Alone In The Old House - Gregor Narholz [Krabs realizes Plankton is still inside the Krusty Krab.]
‣ Martial Tension - Sam Fonteyn [Krabs replaces his nose with SpongeBob's arm.]
‣ Battle at Sea - Johnny Pearson [Plankton blows up Krabs' safe.]
• Hot Steel and Slide Licks 14A - Jeremy Wakefield [Safe opens revealing another safe.]
‣ What Shall We Do with the Drunken Sailor? - Okko Bekker [Mr. Krabs squishes Plankton.]
‣ Glory Road - Sam Fonteyn [The skunk is removed from the Krusty Krab.]
• Hot Steel and Slide Licks 17A - Jeremy Wakefield [Skunk floats into town.]
• Hot Steel and Slide Licks 11C - Jeremy Wakefield [People running out of town.]
• Mission Improbable - Nicolas Carr, Barry Anthony [Krabs tells SpongeBob to hide the secret formula in his house.]
‣ Stool Pigeon - Kenny Graham ["Oh, you're right, Professor Krabface."]
• Sneaky Panther Pants - Nicolas Carr [SpongeBob talks to Plankton while he takes the formula to his house.]
‣ Evil Horror - Harry Lubin [Plankton spying Gary and SpongeBob.]
‣ Tomfoolery - David Snell [Plankton disguised as a salesman.]
‣ Domestic Fun (A) - Ernest Tomlinson [Plankton appears disguised as a girl scout.]
‣ Domestic Fun (C) - Ernest Tomlinson [Gary slams the door.]
• Hot Steel and Slide Licks 37 - Jeremy Wakefield [Plankton dazed.]
• Humorous Conversation - Nicolas Carr, Barry Anthony [Plankton enters SpongeBob's house.]
• The Fruitcake Vendor - Nicolas Carr, Barry Anthony [Plankton tears the house apart looking for the formula.]
• Silly Bob Conversation 2 - Nicolas Carr, Barry Anthony [Plankton goes up to SpongeBob's bedroom.]
• Great Idea Patrick - Nicolas Carr [Gary gets an idea.]
• Noodly Shenanigans - Nicolas Carr, Barry Anthony [Plankton exits SpongeBob's bedroom.]
• Greenhorn Rag Remix - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Plankton slips on Gary's slime.]
• Greenhorn Rag Remix No Whistle - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Plankton falls into Gary's traps.]
‣ Armed Attack - Jean Clero [Gary hits Plankton.]
‣ Magic Potion 1 [#95] - Harry Bluestone, Emil Cadkin ["Of course! What a fool I've been!"]
‣ Misty Menace - Max Saunders [Plankton enters Gary's shell.]
‣ Tower of Evil - Magnum Opus [Gary's eye chases Plankton.]
‣ Dramatic Bridge 1 - Phil Green [SpongeBob sees his house destroyed]
‣ Misty Menace - Max Saunders [SpongeBob worries about Gary.]
‣ Parallel Dimension - Gregor Narholz [Plankton running through Gary's shell.]
‣ Evil Horror - Harry Lubin [Plankton falls into the center of the shell.]
• Vibe Q Sting - Nicolas Carr ["What's that?"]
• Breathing Underwater - Nicolas Carr ["This is it! Just like I thought!"]
‣ The Oracle - David Farnon [Choir.]
• Parting of the Clouds - Nicolas Carr ["Let me bask in its glory!"]
• 12th Street Rag with Bass - Nicolas Carr, Sage Guyton, Jeremy Wakefield [The ending]
- This episode is available on the SpongeBob SquarePants Vol. 16, Factory Fresh, Complete Ninth Season, Collection Triple, Next 100 Episodes, and The Best 200 Episodes Ever DVDs.
- The title card for this episode is similar to that of "Big Sister Sam."
- This is the first episode since "Yours, Mine and Mine" in season 7 to use "Earl's Revenge" as the title card music.
- This is the fourth episode to air for the July 2016 premiere week. It is also the highest viewed episode in the event.
- This episode marks the first usage of the APM track "Tomfoolery" since the episode "Karate Star," and the first usage of "What Shall We Do with the Drunken Sailor?" since "No Nose Knows."
- However, this currently marks the last use of "What Shall We Do with the Drunken Sailor?" in the main series.
- This is the only use of "Tomfoolery" in season 9.
- This is the second episode where a character, in this instance Mr. Krabs, says "Why you little!," a quote that is commonly associated with Homer Simpson in cartoon world. The first was in "Employee of the Month," when Squidward said this after being trapped by SpongeBob in a ship-in-a-bottle.
- This is the first episode where a main character says, "My leg!;" Plankton uses it after Gary slams the door on him.
- This is the second episode when Plankton disguises himself as a Girl Scout in an attempt to get the secret formula. The first was "Sweet and Sour Squid."
- This is the second episode where SpongeBob lies about his hair. The first was "The Smoking Peanut."
- This is the first episode to contain the word "pineapple" in the title, but not use the same background as others.
- List of objects seen in Gary's shell when Plankton goes inside:
- Magic 8-Ball toy
- A toothbrush
- A clarinet
- A nickel
- A teddy bear
- A treasure chest
- A diamond
- This episode reveals that Plankton hates pineapple.
- On the October 22, 2020 airing, this episode was paired up with "Married to Money."
- This episode reveals that shortly after SpongeBob made his first Krabby Patty, which was featured in "Friend or Foe," he got it bronzed.
- In the German and French dubs, SpongeBob's shopping list was localized with German and French text respectively.
- Ironically, both this and its sister episode, "Salsa Imbecilicus," end with Plankton at sunset.
- In the Croatian dub, the episode title is "Ananasu, čuvaj se!," which translates to "Pineapple, look out!"
- This episode reveals that SpongeBob owns Mermaid Man collectible underpants.
- Plankton is disguised as a Sweetie Patrol Girl and tries to sell Sweetie Patrol Cookies, referencing the Girl Scouts and Girl Scout Cookies.
- The title Pineapple Invasion is a reference to home invasion.
- Some of the characters are not drawn with noses, yet they are able to smell the skunk spray.
- Plankton cannot smell, but tells Gary that he should really use the slime deodorant.
- The safe shows the numbers 15-30-75, when it is supposed to be 15-30-45.