- Dennis (citizen)
- Martha Smith
- Billy (lime fish)
- Incidental 2
- Incidental 47
- Jennifer Millie (normal; Charlie-colored)
- Sheldon (fish)
- Vera Fishbowl
- Nat Peterson
- Cara (normal; blue)
- Nancy Suzy Fish
- Frankie Billy
- Norma Rechid (normal; Abigail Marge-colored)
- Paco (normal; kid version)
- Miss Shell
- Medley Fishbowl
- Nathiel Waters
- Tina Fran
- Incidental 48
- Incidental 106
- Jimmy Gus
- Perch Perkins
- SpongeBob SquarePants
- Daydream SpongeBob Statue
- Gary the Snail
- Monroe Timmy
- Daydream Monroe Timmy
- Eugene H. Krabs
- Incidental 152
- Incidental 105
- Patrick Star
- Squidina's mother
- Bubble Bass
- Gale Rechid
- Harold (red fish)
- Shelly Fishbowl
- Patty Rechid (cameo)
- Susie Rechid
- Miss Rechid
- Old Man Jenkins
- King Neptune (Old Man Jenkins) (debut)
- Old Man Walker
- Senior 6
- Harold Bill Reginald Scott
- Phil (yellow)
- Sandy Cheeks (cameo)
- Squidward Tentacles (cameo)
- Farmer fish (debut)
- Unsatisfied customer (green)
- Husband fish (debut)
- Wife fish (debut)
- Elderly whale (debut)
- Poseidon (mentioned)
- Yellow business fish (debut)
- Pigtails girl (debut)
- Violet girl (debut)
- Some of the elderly fish from "Old Man Patrick"
- What Zit Tooya (green)
- Frank (lifeguard)
- Mevis (very small)
- King Neptune
- Seahorse carrier (debut)
The episode begins at SpongeBob's house, where we see a crowd of people gathering outside. Perch Perkins is reporting on the news that SpongeBob is attempting to dive to the surface of the ocean, and he'll be the first Sea Sponge ever to do so. Inside SpongeBob's house, Gary is rubbing lard on SpongeBob's back, as SpongeBob fantasizes about the upcoming event. In the fantasy, a little kid walks up to a SpongeBob statue who talks to him. The little kid screams and runs away as the fantasy sequence ends, and SpongeBob claims that he has to warm up. SpongeBob attempts to lift some weights, but ends up accidentally throwing the weights out of his house, and exclaims that he's ready. Back outside, Mr. Krabs is seen selling SpongeBob standees. Patrick walks up to one of the standees (thinking that it's the real SpongeBob), and tries to make conversation with it. Patrick thinks SpongeBob is giving him the silent treatment, prompting him to do the same. Bubble Bass, thinking Patrick is a standee, walks up to Mr. Krabs and asks him how much he's worth. Bubble Bass ends up paying 10 dollars for the "standee". SpongeBob then walks out of his house and attempts to do the high sea dive off of an upside down diving board, only to fail, disappointing the crowd of people as they walk away.
SpongeBob questions why he wasn't able to go up, to which Sandy walks up to him and tells him that Olympic divers in Texas use gravity to help them go down, and that he should use anti-gravity to go up. As Sandy walks away, SpongeBob gets an idea and runs inside of his house. He then returns to the upside down diving board, now with balloons tied to his waist, and dives to the surface of the ocean, while Squidward is seen in the background grumbling to himself and picking up trash. As SpongeBob is about to reach the surface of the ocean, he is blocked by a giant island of trash from the surface world, which also causes his balloons to pop. SpongeBob is upset about this at first, but decides to explore the trash island. He plays with a giant telephone and a giant comb, and accidentally runs into a giant building. This causes the objects, as well as a couple of others, to float down to the bottom of the ocean. Just then, a group of fish look on as a farmer uses the giant comb to grow his crops, making the fish assume that these are gifts from Neptune. Nearby, a group of campers use a giant pen to hold up their tent, and a recently married couple use the giant building as a house.
Meanwhile, SpongeBob continues to explore the trash island, but out of nowhere, he is hit in the face by a giant fork. The thrower is none other than Old Man Jenkins, who has gone crazy and thinks he is King Neptune. SpongeBob plays along, claiming to be Poseidon. SpongeBob and Old Man Jenkins then start throwing random giant objects at each other, causing them to float down to the bottom of the ocean. Back in Bikini Bottom, one fish uses a giant knife as a surfboard, and a couple of other fish use a giant vacuum cleaner as a car. A little girl is seen attracting a crowd of people, and excitedly tells them that if they want to receive something from Neptune, they'll have to send him messages using balloons, and the crowd does exactly that. Up on the trash island, Old Man Jenkins examines SpongeBob, and discovers that he's not actually Poseidon, to which SpongeBob points out that Old Man Jenkins isn't Neptune either. Old Man Jenkins explains his backstory on how he ended up on the trash island. One year ago, we see Old Man Jenkins celebrating his birthday party. A fat woman gives Old Man Jenkins about a dozen balloons, causing him to float upward. The old people seem to be apathetic to the situation, and walk back inside. As the flashback ends, a bunch of balloons are seen landing on the island, with different people saying what they want from King Neptune.
Old Man Jenkins wants to go back down to Bikini Bottom to help his "subjects", and SpongeBob gets the idea to build a ladder out of the trash to climb back down. Meanwhile, the Bikini Bottomites are freaking out because no more trash is coming down from the surface. As they are about to sacrifice a woman fish, the ladder that SpongeBob and Old Man Jenkins built reaches the ground. Everyone thinks that if they climb the ladder, it'll lead them to more free stuff. On the surface, SpongeBob finishes building the ladder, as he notices that they are right at the surface. He proudly plants a flag on top of the ocean, and the both of them start climbing down the ladder. They notice that the ladder is shaking, and the Bikini Bottomites see Old Man Jenkins, thinking that he is Neptune. This makes everyone shake the ladder even harder, but SpongeBob explains that he dove up to the surface of the ocean and found Old man Jenkins living among the objects. The people exclaim that SpongeBob is the one that sent down the objects and call him a hero. The ladder ends up shaking so much that it completely collapses and spreads trash throughout Bikini Bottom. Old Man Jenkins surfaces out of the trash, still claiming to be King Neptune. Suddenly, the real King Neptune shows up, and smites Old Man Jenkins with his trident. Mr. Krabs approaches the massive trash pile and pulls a flattened SpongeBob out of it. He thinks SpongeBob is another one of his standees and throws him in the back of his truck and drives off. SpongeBob reflects on how the citizens of Bikini Bottom called him a hero, as the episode ends.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
• SpongeBob Theme II - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Title card.]
• Bikini Bottom News Theme - Nicolas Carr ["Perch Perkins here for Bikini Bottom News."]
‣ Against All Odds - Paul Lawler ["Today, SpongeBob SquarePants will attempt the impossible!"]
• Hot Steel and Slide Licks 23 - Jeremy Wakefield [Gary greases SpongeBob's back.]
• Proud to Be a Fish - Nicolas Carr, Barry Anthony [SpongeBob imagines a statue of himself.]
‣ Steve's March - Sam Spence [SpongeBob trying to lift weights.]
• Jovial Pirate's Jig - Michael Bolger, Nicolas Carr [Krabs selling SpongeBob's souvenirs.]
• A Fishy Conversation - Barry Anthony ["Hey, SpongeBob, what's new?"]
‣ Adventure - Ronald Hanmer [SpongeBob steps to the diving board.]
‣ ? [Drumroll.]
‣ Circus Parade (b) - Dick Walter [SpongeBob jumps off the diving board.]
• Hot Steel and Slide Licks 22 - Jeremy Wakefield [Everyone walks away.]
• Hot Steel and Slide Licks 9 - Jeremy Wakefield ["I just don't understand it."/"Anti-gravity?"]
• Great Idea Patrick - Nicolas Carr [Light bulbs come out of SpongeBob's head.]
‣ Fantasy Caper 1 - Paul Lawler [SpongeBob jumps off the diving board with balloons tied.]
‣ End the Show 1 - Barry Tattenhall ["I'm doing it! I'm doing it!"]
‣ Dinosaurs About - John Fox, Mac Prindy [Sea surface is full of trash.]
• Vibe Q Sting - Nicolas Carr ["Hmm?"]
‣ The Ocean - Gregor Narholz [SpongeBob walking through the trash surface.]
‣ Mystery Harp - Nicolas Carr [SpongeBob playing comb like a harp.]
‣ The Ocean - Gregor Narholz [SpongeBob continues walking through the trash surface.]
• Lap Steel - Nicolas Carr [Transition to next scene.]
‣ ? [Nicolas Carr]
• Skipping to Hillbilly School - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Farmer puts comb on the back of his tractor.]
• Birth of the Krabby Patty - Nicolas Carr ["It's a gift!"]
‣ Boy Scout - Harold Smart [Scouts building a tent.]
‣ Shotgun Wedding 2 - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Married couple arrive at home.]
‣ Four More Comical Cuts - Ronald Hanmer ["I'm sorry, honey. I couldn't afford the whole house, just the door."/Wife's mother is shown.]
‣ This Space for Hire - Sam Fonteyn [SpongeBob sees someone at the trash surface.]
‣ Circus Maximus - Jean-Pierre Fouquey ["Feel my power!"]
• What the Huh Vibe Sting - Nicolas Carr ["Old Man Jenkins?"]
• Hot Steel and Slide Licks 20 - Jeremy Wakefield ["I'm not Old Man Jenkins anymore, I'm King Neptune!"]
• Grass Skirt Chase - Sage Guyton, Jeremy Wakefield [SpongeBob and Old Man Jenkins throwing trash at each other.]
‣ World of Fantasy - Gregor Narholz [Bikini Bottomites blowing up balloons with messages.]
• A Simple Conversation - Nicolas Carr, Barry Anthony ["You're not Poseidon, you're SpongeBob SquarePants."]
• Hot Steel and Slide Licks 3 - Jeremy Wakefield ["And you're Old Man Jenkins."]
‣ Aloha Oe - Hans Haider, Queen Lili'uokalan [Old Man Jenkins' birthday party at Shady Shoals.]
• Hot Steel and Slide Licks 6 - Jeremy Wakefield [Balloons popping and revealing messages.]
• Seaweed - Steve Belfer [SpongeBob building a ladder out of garbage.]
‣ Dramatic Cue (e) - Ronald Hanmer ["Why isn't Neptune sending more gifts down for us?"]
• Five Divas Singing - Nicolas Carr [Choir.]
• SpongeBob Theme II - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Everyone climbing the ladder.]
• Hot Steel and Slide Licks 28 - Jeremy Wakefield [SpongeBob puts the last object into the ladder.]
‣ Achievements in Aviation - Anthony Mawer ["Hey, look at that!"]
• Hot Steel and Slide Licks 22 - Jeremy Wakefield [SpongeBob and Old Man Jenkins climbing down the ladder.]
• Who Said That - Nicolas Carr, Barry Anthony ["Stop shaking the ladder!"]
‣ Requiem, Sanctus - Giuseppe Verdi ["I think I see him! It's Neptune!"]
• Hot Steel and Slide Licks 4 - Jeremy Wakefield [Ladder staggering.]
• Porous Pursuit - Nicolas Carr, Sage Guyton, Jeremy Wakefield ["It's Old Man Jenkins!"]
• Hot Steel and Slide Licks 36 - Jeremy Wakefield ["Hey, it's SpongeBob!"]
‣ Caesar's Entry [#7.2] - Gregor Narholz ["Hooray for SpongeBob, he's our hero!"]
• Slide Whistle Stooges - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Trash ladder collapses.]
• Hot Steel and Slide Licks 26 - Jeremy Wakefield [Everyone stuck in trash pile.]
‣ Salute to Caesar 2 - Gregor Narholz ["I'm King Neptune, king of the seven seas!"]
‣ The Pursuit of Power (a) - Keith Mansfield [Real King Neptune appears.]
‣ The Pursuit of Power (b) - Keith Mansfield [King Neptune zaps Old Man Jenkins.]
• Hot Steel and Slide Licks 5 - Jeremy Wakefield ["I smell like toast."]
• Galley Cooks Shanty 3 - Michael Bolger, Nicolas Carr [Ending.]
- This episode is available on the SpongeBob SquarePants Vol. 18 and The Complete Eleventh Season DVDs.
- When this episode originally aired, it was paired with a rerun of "Bunny Hunt." 
- The Great Pacific garbage patch is seen in this episode and acts as a barrier that prevents SpongeBob from reaching the surface of the ocean.
- This is the only season 11 episode where Incidental 103 appears.
- Despite Mr. Krabs' love of money and his knowledge in business, he is noticeably scammed by Bubble Bass in this episode, agreeing to give away Patrick for half the original price due to Bubble Bass claiming he is damaged.
- This is the ninth 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," the fourth is "SpongeGuard on Duty" (not counting live-action SpongeBob costume), the fifth is "Mermaid Man vs. SpongeBob," the sixth is "The Inmates of Summer," the seventh is "Jailbreak!," and the eighth is "Don't Wake Patrick."
- This episode formerly held the record for the least-watched episode of the entire series, accumulating a total of only 1.21 million U.S. viewers, beating the previous record holder, "Sanctuary!," which gained 1.28 million U.S. viewers. This record would not be broken until "ChefBob" having 1.04 million U.S. viewers.
- The way Bikini Bottomites send balloon messages to "King Neptune" is similar to the way Patrick and SpongeBob send bubble messages in "Naughty Nautical Neighbors."
- The acts of SpongeBob cleaning the ocean surface and the townsfolk finding better use for the trash is an important message to viewers to help stop water pollution and recycle trash.
- This is the last usage for the track "Hot Steel and Slide Licks 23" to play, until "Knock Knock, Who's There?"
- This is Old Man Jenkins' first ever major appearance in an episode.
- The episode's title comes from deep sea diving.
- When the Bikini Bottomites blow up balloons to send their wishes to "King Neptune," they do not knot them to keep the air in, with the balloons immediately knotting themselves.
- Most of the objects are floating up in the sea, but when SpongeBob and Old Man Jenkins are throwing them at each other, they sink.
- ^ https://twitter.com/VincentWaller72/status/947672020849971201
- ^ (nickstory.fandom.com/wiki/April_6,_2018)