- Realistic Fish Head
- Barnacle Boy
- Mermaid Man
- Man Ray
- Sheldon J. Plankton
- Professor Plankton (debut)
- Incidental 37A (child)
- Incidental 150 (103-colored)
- Incidental 103
- Incidental 152
- Incidental 151
- Incidental 153
- Incidental 141
- Incidental 142
- Incidental 143
- Incidental 144
- Blue kid fish
- Unnamed light-green fish (purple)
- Green kid fish
- Incidental 109
- Incidental 48 (child, green)
- Squidward Tentacles
- Eugene H. Krabs
- SpongeBob SquarePants
- Fry Boy (debut)
- Karen Plankton
- Incidental 31
- Incidental 9
- Incidental 27
- Incidental 49
- Incidental 64
- Incidental 6
- Incidental 48
- Incidental 108
- Incidental 40
- Incidental 106
- Incidental 46
- Incidental 41
- Incidental 73
- Incidental 45
- Incidental 92
- Incidental 93
- Incidental 91
- Old Man Walker
- Incidental 82
- Incidental 84
- Incidental 81
- Incidental 119
- Incidental 87
- Incidental 80
- Shady Shoals caretaker
- Incidental 14
- Weenie 1
- Perch Perkins
- Incidental 7 (named Susie)
- Ted (fish)
- Incidental 104
- Incidental 67
- Incidental 3
- Incidental 5
- Incidental 37B
- Incidental 60
- Incidental 12
- Incidental 2
- Incidental 69
- Incidental 68
- Incidental 63
- Incidental 47
- Incidental 23
- Incidental 65
- Incidental 16
- Incidental 42
- Incidental 10
- Incidental 36
- Incidental 22
- Incidental 13
- Incidental 15
- Incidental 90
- Incidental 20
- Incidental 4
The episode starts with a commercial of Mermaid Man and Barnacle Boy on a conveyor belt, tied up in chains by Man Ray. The heroes cannot escape. Mermaid Man then starts talking about the Krusty Kid's Meal at the Krusty Krab, which Man Ray asks Mermaid Man what it is.
The next scene shows Man Ray eating the Pipsqueak Patty, small fries, and drinking the juice box. The narrator of the commercial responds by saying, "Of course you do, Man Ray." The kids off-screen of the commercial scream joyfully. In the next scene, Man Ray is in chains, holding up the Krusty Kid's Meal box with Mermaid Man and Barnacle Boy beside him as the commercial ends.
Plankton is annoyed by the commercial, seeing all of the kids at the Krusty Krab through his periscope. Mr. Krabs' profits increase, as children flock to the Krusty Krab. Plankton decides to use mind control shampoo to turn Mermaid Man and Barnacle Boy against Mr. Krabs and SpongeBob.
Plankton controls Mermaid Man to say hateful things about Krabby Patties, resulting in all the Krusty Krab customers resorting to the Chum Bucket. Then, SpongeBob brings a big truck of fiber and feeds it to Mermaid Man and Barnacle Boy forcefully, which brings them back to normal.
Then everyone goes back to the Krusty Krab. When Plankton brings out a plate of Chummy Joes he prepared, he screams as he sees the customers gone, ending the episode.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ The Lineman - Sam Spence [Title card]
‣ Caped Crusader - David Farnon [Opening]
‣ Police Car - Sam Spence [Shot of the kids meal]
‣ The Four Horseman - Ronald Hanmer [Man Ray laughs]
‣ Tripping Along - Harry Bluestone, Emil Cadkin ["Ooh, I just love the little Pipsqueak Patty..."]
• Mermaid Man Sting - Nicolas Carr ["Of course you do, Man Ray!"]
‣ Captain Pugwash - Johnny Pearson [End of the Krusty Kid's Meal commercial]
‣ Zelle 501 - Gerhard Trede [Plankton watches TV]
‣ Life on the Wild Side - Sam Spence ["Something is going on over there!"]
‣ The Tip Top Polka/The Cliff Polka - Chelmsford Folk Band ["Gotta hand it to you, boy."]
• What's This - Nicolas Carr ["Wait a minute, what's this?"]
‣ Wooden Bear - Gil Flat, Tony Tape, Florian Voelxen [Karen brings Plankton a kids meal box.]
• Steel Sting - Jeremy Wakefield [Plankton smashes the box up.]
‣ Death Trap - Gregor Narholz ["Why didn't I think of this before?"]
‣ Hawaiian Link (b) - Richard Myhill [Exterior of Shady Shoals Rest Home]
‣ Sweet and Lovely - Alan Braden [Plankton pretends to be a salesman]
‣ Frankenstein's Niece A - Gregor Narholz [Plankton uses mind-control shampoo on Mermaid Man and Barnacle Boy]
• Mermaid Man Sting - Nicolas Carr [WIPE!]
‣ Bring on the Girls - Dennis Farnon [Back at the Krusty Krab...]
• Steel Licks 8 - Jeremy Wakefield [Kids run into the ball room]
• Unknown Track 75 - "Aye aye, Mr. Krabs!"
‣ Abject Terror - Paul Lewis [Mermaid Man and Barnacle Boy destroy the rest home.]
• Steel Licks 2 - Jeremy Wakefield ["You guys live in a dump."]
• Grass Skirt Chase - Sage Guyton, Jeremy Wakefield [Mermaid Man beats up SpongeBob]
• Closing the Door - Nicolas Carr ["You still got it."]
• Bikini Bottom News Theme - Nicolas Carr [News report]
‣ Kerry Polka - Brian Peters [Mr. Krabs interviewed]
‣ Editor's Falling Over (a) - Dick Stephen Walter [SpongeBob crashes through the roof]
‣ Blaze of Brass (d) - Cecil Milner ["Ladies and gentlemen, I present Mermaid Man and Barnacle Boy!"]
‣ Police Car - Sam Spence [Sting]
‣ House of Horror - William Farran ["Everyone in Bikini Bottom showed up!"]
• Goofy Conversation - Nicolas Carr, Barry Anthony ["Ooh, this is too easy!"]
• Parting of the Clouds - Nicolas Carr [Shot of the Krabby Patty]
‣ House of Horror - Larry Hochman ["Why, these things are... evil!"]
• Harp! - Nicolas Carr ["You forgot your Krabby Patties!"]
‣ Black Stockings - David Lindup [Mermaid Man and Barnacle Boy drool]
‣ House of Horror - William Farran [Mermaid Man and Barnacle Boy stomp on the Krabby Patty]
‣ Adventurers - Larry Hochman ["Fry Boy, defender of...!"/"Fry Boy, defender of the Krabby Patty!"]
‣ Ramblin' Man from Gramblin' - Sam Spence [SpongeBob fights Mermaid Man and Barnacle Boy]
‣ Robot March - Harry Bluestone, Emil Cadkin [Mermaid Man and Barnacle Boy run to the Chum Bucket.]
• Idea Vibe - Nicolas Carr ["Food?"]
• Steel Licks 3 - Jeremy Wakefield ["It doesn't make sense."/"Their poor aging tummies must be having a hard time digesting the food."]
‣ The Lineman - Sam Spence [A fiber truck breaks into the Chum Bucket]
‣ Dancing the Hula - Kapono Beamer [Mermaid Man and Barnacle Boy turn back to normal]
‣ Arizona Fanfare - Jack Shaindlin ["To the Krusty Krab, away!"]
• Goofy Conversation - Nicolas Carr, Barry Anthony [Ending]
- This episode is available on the To Love a Patty, Season 5 Volume 2, First 100 Episodes, Holidays with SpongeBob 3-DVD Gift Set, Mermaid Man & Barnacle Boy: Defenders of the Deep, From the Beginning, Pt.2, SpongeBob SquarePants Vol. 8, Kids Double Pack: Volume 6, The Ultimate SpongeBob Box Set, The SpongeBob SquarePants Collection, The SpongeBob SquarePants 8 Season DVD Collection, Easter with SpongeBob, Complete Fifth Season, The Adventures of SpongeBob SquarePants, and The Best 200 Episodes Ever DVDs.
- It is also a bonus feature on the Back at the Barnyard:Lights, Camera, Moo! DVD in the UK.
- "Mermaid Man vs. SpongeBob" was ranked #48 during the SpongeBob's Top 100 event in the UK and Ireland from June 4-8, 2012.
- In "Mermaid Man and Barnacle Boy V," Barnacle Boy balks at the idea that he be served a Pipsqueak Patty instead of an adult-sized Krabby Patty. At the beginning, in the commercial, he and Mermaid Man promote the Krusty Kid's Meal, the main course being an actual Pipsqueak Patty.
- Squidward delivers six boxes of Krusty Kid's Meal to the "Tarpon twins." The tarpon is a type of fish.
- After the Krusty Kid's Meal commercial, one can see that Karen is at the Krusty Krab getting a Krusty Kid's Meal, even though usually Karen would have been the screen Plankton watched the commercial on in the first place.
- Off-screen, Karen has left from the Chum Bucket to the Krusty Krab.
- "My leg!:" Faintly heard as Mermaid Man and Barnacle Boy are destroying the Shady Shoals Rest Home while under Plankton's control.
- The part where SpongeBob says, "Fry Boy, defender of the Krabby Patty!" is similar to when he says, "The hall monitor!" in the episode "Hall Monitor."
- This is the first episode to use two different versions of "House of Horror." There is version 1 of William Farran's "House of Horror" and version 2 of Larry Hochman's "House of Horror."
- This is the first Mermaid Man and Barnacle Boy episode to not have Barnacle Boy or Roman numerals in the title.
- This is the first episode where Man Ray is voiced by Bob Joles instead of John Rhys-Davies. Man Ray was previously voiced by John Rhys-Davies in the episodes "Mermaid Man and Barnacle Boy III" and "Mermaid Man and Barnacle Boy V."
- This episode marks the second time Plankton says "Stupid kid." The first is in The SpongeBob SquarePants Movie.
- This is the second time where Patrick does not appear in a Mermaid Man and Barnacle Boy episode. The first time is in "Mermaid Man and Barnacle Boy II."
- This is the third episode to contain a title of two characters versing each other. The first is "Krabs vs. Plankton," and the second is "SpongeBob vs. The Patty Gadget."
- This is the fifth episode in which, at no point, SpongeBob wears his normal clothes. The first is "Ripped Pants," the second is "Walking Small," the third is "The Fry Cook Games," and the fourth is "SpongeGuard on Duty" (not counting the live-action SpongeBob costume).
- Amazon Prime calls this episode "Mermaid Man Vs Sponge."
- The badly-played fanfare accenting the shot of SpongeBob grinning in his superhero outfit (also heard in "A Flea in Her Dome" and "Appointment TV," which was performed by Stephen Hillenburg himself according to a tweet by sound designer Jeffrey Hutchins.
- In the Filipino dub, Mermaid Man's voice is lower pitched in this episode, and he sounds more like Patrick.
- That is because they are both dubbed by the same person, Jojo Galvez.
- Chummy Joes are a parody of sloppy joes.
- One of the hexagonal faces on the side of the Krusty Kid's Meal that is first shown is Mr. Krabs with a happy face behind the trapezium-shaped, light blue and pale background. However, in the next scene, the upper light blue trapezium shape extends to the light blue hexagonal shape that covers the upper dark olive green part of the Krusty Kid's Meal, causing Mr. Krabs’ eyes and claws to be shifted upwards.
- Also, two letter M's are missing on the next top right part of the Krusty Kid's Meal.
- When Mermaid Man does the spine blaster on SpongeBob, one can see the latter's leg bones, even though sponges are invertebrates.
- When Karen comes into the Chum Bucket with the Krusty Kid's Meal, the box does not have the logos on it.
- The "with conditioner" part of the Prof. Plankton's Mind Control Shampoo bottle disappears right after Professor Plankton mentions it.
- The openings on the net of the ball room are big enough for the balls to roll out of.
- When Mr. Krabs locks the kids in the ball room, two kids begin to climb up the wall.
- In the next shot, the kids are gone.
- Right before SpongeBob takes off to find Mermaid Man and Barnacle Boy, his eyelashes disappear for one frame.
- Before the crowd leaves the Krusty Krab, Mr. Krabs says "wait," but he is not heard speaking when he says that line.