- Nancy Suzy Fish
- Nat Peterson
- Sheldon J. Plankton
- Squidward Tentacles
- King Neptune (mentioned)
- Tina Fran
- Eugene H. Krabs
- SpongeBob SquarePants
- Debbie Rechid
- Baby Rechid
- Norma Rechid
- Mama Plankton (mentioned)
- Officer John Slugfish
- Lady officer
- Karen Plankton
- Miss Shell
- Old Man Jenkins
- Mable the Gray Fish
- Baby Billy (debut)
- Martha Smith
- Sheldon the Fish
- Patrick Star
- Harold "Bill" Reginald
The scene starts with Plankton (disguised as a pepper shaker) taking a Krabby Patty but is easily caught by Mr. Krabs. As he is lamenting his failure on a bench in the park, Plankton then hears a woman saying that she can take her baby's milk away from him and he cannot do a thing about it. This makes Plankton realize he will turn Mr. Krabs into a baby.
Plankton then leads Mr. Krabs in a telephone booth by money where he sprays Goo Goo Gas on him, turning Mr. Krabs into a baby but Baby Krabs teeths on Plankton. SpongeBob finds Baby Krabs and takes him, but Plankton accidentally reveals to an overhearing SpongeBob that Baby Krabs is Mr. Krabs and his plans. SpongeBob calls the cops and Plankton gets arrested, but easily escapes. SpongeBob explains everything to an arriving Squidward who immediately leaves. SpongeBob takes the baby in the Krusty Krab and tries to comfort him with many items, eventually succeeding with a stack of twenties.
Meanwhile, Plankton sprays Baby Krabs and SpongeBob but Mr. Krabs is now an adult and SpongeBob is a baby. Plankton squirts SpongeBob and he is now an adult again. The same thing happens again, and Plankton thinks it was not right. However, he gets launched out of the Krusty Krab by Mr. Krabs again. Later, Plankton uses a new spray, and sprays Mr. Krabs again. However, he notices Mr. Krabs is now elderly, realizing it was Senior Citizen Spray.
Soon, SpongeBob appears out of nowhere and says a speech about caring for Senior Citizens. However, Plankton sprays him as well, and then says that they cannot catch him. Both SpongeBob and Mr. Krabs then trap Plankton by knitting a net, getting hit one by one by senior citizens.
Plankton then realizes that there is one ingredient that he is missing to turn people into babies.
He goes to Barg'N-Mart where he buys baby powder and then goes back to complete the experiment. Using Karen as a test subject, it works. He then returns to the Krusty Krab and sprays all the customers, including SpongeBob, Patrick, Squidward, and Mr. Krabs and they remain stuck as babies for the rest of the episode. Plankton is about to get the formula when he gets beaten up by the babies.
Baby SpongeBob begins playing with the gas canister, bashing it on the ground. It flies into the air and releases gas everywhere, turning Plankton into a microscopic baby. As the episode ends, Baby Plankton says "Ahem, Momma's evil little genius needs a diaper!"
Originally, in the scene where Plankton sits on the bench and watches the baby, Plankton would take a baby bottle a few times and then kidnap the baby. The baby's mother would then walk up to the stroller and ask where her baby went. It was heavily implied in the audio commentary that Sadie was not going to be the baby's mother, so it was later cut.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Towerstreet 17 [#10] - Gerhard Narholz [Plankton steals a Krabby Patty]
‣ Towerstreet 17 [#4] - Gerhard Narholz ["Hold it right there, Plankton."]
‣ Towerstreet 17 [#33] - Gerhard Narholz [Krabs takes the patty from Plankton]
‣ Unknown Track 40 - Nicolas Carr [Plankton launched back to Chum Bucket]
‣ Solo Steel - Jeremy Wakefield [Plankton on a park bench]
‣ Vibe Q Sting - Nicolas Carr ["Aw, look at you!"]
‣ Twinkle Toes - Fred Woods [Woman talking to baby]
‣ Unknown Track 48 - "Something about that woman reminds me of my mother."
‣ Harp Ding - Nicolas Carr ["That's it!"]
‣ Zelle 501 - Gerhard Trede [Plankton think about turn Krabs into a baby]
‣ Krusty Krab Tango - Steve Marston [Trail of pennies]
‣ Life or Death - Jack Beaver [Phone booth fills with gas]
‣ Tomfoolery - David Snell [Krabs as a baby]
‣ Against the Law (a) - Wilfred William Burns ["Yes! My plan is working perfectly!"]
‣ International Law - Peter Yorke [Plankton arrested]
‣ Vibe Sting - Nicolas Carr [Plankton frees himself]
‣ Steel Licks (a) - Jeremy Wakefield [Police chase Plankton]
‣ Acts of Heroism (a) - Trevor Duncan ["Oh, Squidward, thank Neptune you're here."]
‣ Drama Link (e) - Hubert Clifford ["What do we do, Squidward?"]
‣ Goofy Conversation - Nicolas Carr, Barry Anthony [At the Chum Bucket]
‣ Cartoon Sting 6 - Baby Krabs crying
‣ Kommissar X - Gerhard Trede [Plankton sprays SpongeBob and Krabs/Plankton sprays SpongeBob and Krabs again]
‣ Keel Row - Brian Peters [Krabs throws Plankton back to Chum Bucket]
‣ From the Dead - Ronald Hanmer [Plankton comes out of Krabs' mailbox]
‣ Death Trap - Gregor F. Narholz [Plankton chasing Krabs]
‣ Closing the Door - Nicolas Carr [Plankton sprays Krabs]
‣ Comic Walk - Sidney Torch [Krabs as a senior citizen]
‣ The Adventure Begins - Jonathan Neal ["Hold it right there."]
‣ Land of the Bard - Raymond C. Jones ["Old people are our greatest natural resource."]
‣ Comic Walk - Sidney Torch [SpongeBob as a senior citizen]
‣ From the Dead - Ronald Hanmer [Plankton steals a Krabby Patty]
‣ Twelfth Street Rag - Sage Guyton, Jeremy Wakefield [SpongeBob and Krabs stop him]
‣ Jarabe Tapatio (a) - Gerhart Frei, Carlos Periguez [Pinata party]
‣ Mission Improbable - Nicolas Carr, Barry Anthony [Plankton doing math equations]
‣ Happy-Go-Lively - Laurie Johnson [Plankton at Barg'N-Mart]
‣ Like Strange - Kenny Graham [Plankton tests his baby gas on Karen]
‣ Zelle 503 - Gerhard Trede [Plankton turning everyone into babies]
‣ Cartoon Sting 6 - Babies drooling on Plankton
‣ Parting of the Clouds - Nicolas Carr ["I don't believe it! The Krabby Patty formula!"]
‣ Cartoon Sting 6 - Baby Krabs hits Plankton with the formula bottle
‣ Cellar Search - Philippe Pares ["I've got it!"]
‣ Cartoon Sting 6 - SpongeBob playing with gas container
‣ Cosmic Cloud - Trevor Duncan [Ending]
- This episode is available on the SpongeBob's WhoBob WhatPants?, Season 5 Volume 2, Complete Fifth Season, and First 100 Episodes DVDs.
- As of June 10, 2019, The Internet Movie Database (IMDB) gives this episode a rating of 7.2/10 based on 205 ratings by users. TV.com users give this episode a rating of 8.8/10 based on 199 votes.
- Although this episode was made in 2007 according to the credits, it never aired in the United States until two years later in 2009.
- This is the only episode from season 5 to air in 2009 and the only to be one of the 11 new episodes in The Ultimate SpongeBob SpongeBash.
- This episode aired as one of the 10 new episodes during The Ultimate SpongeBob SpongeBash and officially completed season 5.
- This is the last season 5 episode to air, in order of airing appearance (not production order).
- On June 15, 2011, the television airing changed the air date to September 29, 2007, because that is when the sister episode first aired. It used to be listed as July 19, 2009.
- When this episode premiered on television in the United States, it was paired with "No Hat for Pat."
- This episode aired in Germany on November 14, 2007 which was two years before it premiered in the USA.
- This episode premiered in the UK on September 27, 2008, before it premiered in the USA.
- This episode premiered in the UK four years after Nicktoons The Show Must Go On! was released and three years after the release of The Complete 3rd Season and SpongeBob Goes to the Doctor.
- This episode was available on the SpongeBob's WhoBob WhatPants? and Season 5 Volume 2 DVDs before it aired on TV in the USA.
- The German version of this episode lacks the text font, color, and background in the title card design.
- This is the first time a telephone booth is seen outside the Krusty Krab. Some other times, a Pay Phone can be seen on the back of the Krusty Krab or nearby.
- On some airings of this episode, during the scene where Plankton says, "Barnacles, I've run out of gas!," the closed-captions instead read "Particles, I've run out of gas!"
- SpongeBob says that, "Old people are our greatest natural resource," which references "Mermaid Man and Barnacle Boy" when he says, "Old people are the greatest."
- The scenes with Old SpongeBob and Old Mr. Krabs were featured on the fake promo for Nickelodeon UK channel called "Nick Sr." during April Fool's Day.
- When Plankton turns SpongeBob and Mr. Krabs old, a walker and a cane are seen. It is unknown how they got it.
- When Karen is sprayed with the gas, she turns into a calculator and displays "HELLO" while turned upside down, which would be the number "0.7734."
- When Plankton turns into a baby, he simply shrinks to microscopic size and can still talk like he could before.
- This is Dennis' 50th episode appearance.
- This is also Billy's 25th episode appearance.
- Plankton calls Mr. Krabs "Methuselah," who in the Hebrew Bible, is the oldest person.
- In this episode, the key to the Krusty Krab does not have two Ks, unlike in other episodes where it has been seen.
- When Plankton comes out of the mailbox, Mr. Krabs eyebrows are not filled in.
- When Nat sees SpongeBob chasing Plankton, he is at the right side of the table he is sitting next to. When the shot shows Mr. Krabs, he is at the left side of the screen.
- When Plankton gets trapped in the net, the Krabby Patty he had is suddenly missing.
- The openings on the net were big enough for Plankton to jump out of.
- The net Plankton gets caught in is not held by anything. A trap net will not work unless the supporting string is tied to something.
- When Karen is in calculator form, she writes "hello" in numbers. However, there is no period between the 0 and the first 7, which is the only way to make "hello" with a calculator. However, some calculators don't need points to say "hello" between the 0 and first 7.
- Plankton is microscopic as a baby in this episode, but in "Friend or Foe," he is the roughly his regular size as a baby.
- When Plankton turns the adults into babies they end up diapered after being sprayed. However, when Plankton is turned into a baby he is the only one who doesn't get one, perhaps due to him now being microscopic.