- Patrick Star
- SpongeBob SquarePants
- Squidward Tentacles
- Incidental 107
- Jellyfish (cameo in painting)
- Gary the Snail (cameo)
- Incidental 40
- Incidental 37B
- Incidental 73
- Incidental 47
- Incidental 151
- Sheldon J. Plankton (cameo)
- Incidental 27
- Incidental 41
- Incidental 6
- Incidental 2
In the beginning of the episode, it is a beautiful day on Conch Street, where SpongeBob and Patrick are giggling and playing by running back and forth between their houses. Squidward finally opens up his blinds to look out of his window, and this annoys him because they are running in his yard the whole time. He finally loses his temper and walks outside to confront them. He stops SpongeBob and Patrick with two suction cups and screams at them about playing in his yard. SpongeBob explains to Squidward about doing so, and that they're using his yard as a walkway. Squidward now wants to make them choose which one of their yards to play in, and leave his yard out of the situation. Patrick thinks he's good at choosing, but can't decide which yard to play in that day, and finally lets Squidward choose.
He puts SpongeBob and Patrick in their own yards and draws a box around his to prevent SpongeBob or Patrick from going in it, and then goes inside his own house.
The two panic and think that they will never see each other again. SpongeBob tries to walk across the road, but the traffic is terrible, and just at that moment wants Patrick to do something. Patrick tries to squeeze himself into the mailbox in order to get to SpongeBob's house, but the mailbox breaks and explodes. SpongeBob wants Patrick to sit tight, ties himself to the mailbox, and slingshots himself over to Patrick, but it doesn't work. SpongeBob now has an idea and wants Patrick to see so they think to dig a tunnel underneath their houses.
They eventually meet up and start playing. Squidward can hear them playing, so he goes outside, but they are not in his yard. He looks in SpongeBob's and Patrick's houses, but they are not there either. He can't find them anywhere and eventually, this sends Squidward into a rage as he believes SpongeBob and Patrick have finally become ghosts, so he shouts "Where are they?!" and starts jumping up and down. This causes the roots underground to wiggle, and SpongeBob and Patrick think they are dancing, so they start doing so.
This sinks Squidward's house and he finally realizes that they've been underground the whole time, so he enters his house through the roof hatch. Squidward comes out of his house and makes SpongeBob and Patrick dig it back out while he relaxes, but Patrick accidentally breaks Squidward's window and SpongeBob accidentally lets all the dirt flood Squidward and himself out of the house. Squidward threatens SpongeBob and Patrick if they don't obey him and dig out his house by the count of 3, Squidward will turn them into chum, which frightens them.
SpongeBob and Patrick dig more, but when Squidward reaches 3, they start running away in panic from Squidward, digging more tunnels. As they are doing this, SpongeBob and Patrick sink all the buildings in Bikini Bottom, including their own houses, downtown, and even the Krusty Krab. Plankton then realizes that the Chum Bucket is the only restaurant in town, but it sinks too.
After a whole lot of digging, SpongeBob and Patrick come to a rock and a furious Squidward corners toward them. After he yells at them, all of Bikini Bottom sinks underground. Sometime later, SpongeBob, Squidward, and the other Bikini Bottomites dig out Bikini Bottom.
The episode ends with SpongeBob saying "Another beautiful day under Bikini Bottom," and Squidward putting on a mining helmet and saying "I hate neighbors."
- Buildings sinking underground when SpongeBob and Patrick dig too much under them.
- Squidward growling.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
• Cream Pie - Sage Guyton, Jeremy Wakefield [Title card]
• Seaweed 2 - Steve Belfer [SpongeBob and Patrick running back and forth between their houses]
• Who Said That - Nicolas Carr, Barry Anthony [Squidward's angry]
• Flextone Sting - Nicolas Carr [SpongeBob and Patrick look at each other]
• Light Conversation 1 - Nicolas Carr, Barry Anthony ["We're not playing in your yard, Squidward, we're playing in our yards!"/"SpongeBob's! I'm terrible at choosing! Squidward! You choose!"]
‣ Unsettled Menace - Phil Green ["SpongeBob!"]
‣ Armed Attack - Jean Clero ["Patrick, what are we gonna do?"]
‣ Unsettled Menace - Phil Green ["I'll mail myself to your house!"]
‣ Sea Battle [#44] - John Fox ["Sit tight, Patrick! I'm coming to get you!"]
• Steel Licks 8 - Jeremy Wakefield [SpongeBob, Patrick go back into their houses]
• Vibe Q Sting - Nicolas Carr ["Hmm...have we ever dug a tunnel between our two houses?"]
• Slide Whistle Stooges - Nicolas Carr, Sage Guyton, Jeremy Wakefield [SpongeBob and Patrick digging a tunnel between their houses]
• Solo Steel 3 - Jeremy Wakefield [Squidward sleeping]
• Noodly Shenanigans - Nicolas Carr, Barry Anthony ["Peek-a-boo, I see you!"]
• Solo Steel 2 - Jeremy Wakefield [Squidward goes back to sleep]
• Noodly Shenanigans - Nicolas Carr, Barry Anthony [Squidward is woken up by SpongeBob and Patrick]
• Tension Bits - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Squidward gets angry]
• Descent Into Madness - Nicolas Carr [Squidward's yard empty/Patrick's house empty/SpongeBob's house empty]
• The Pollywog Strut - Nicolas Carr, Barry Anthony [Gary on the roof]
• Down in Davey Jones Locker - Nicolas Carr ["Where are they?!"]
• Slide Whistle Stooges - Nicolas Carr, Sage Guyton, Jeremy Wakefield [SpongeBob and Patrick stomping]
• Steel Licks 10 - Jeremy Wakefield [Squidward's house underground]
• Steel Sting - Jeremy Wakefield ["It ate Squidward."]
• Gator - Steve Belfer ["I knew you two reprobates were behind this."]
• Slide Whistle Stooges - Nicolas Carr, Sage Guyton, Jeremy Wakefield [Squidward chases SpongeBob and Patrick]
• Lap Steel - Nicolas Carr ["Oh, boy!"]
• Skipping to School - Sage Guyton, Jeremy Wakefield [Squidward goes back into his house]
• Tension Bits - Nicolas Carr, Sage Guyton, Jeremy Wakefield ["One!"]
• Tension Times Two - Nicolas Carr ["It's counting! Anything but counting!"]
• Tension Bits - Nicolas Carr, Sage Guyton, Jeremy Wakefield ["Two!"]
• Tension Times Two - Nicolas Carr ["He's already at number two!"]
• Tension Bits - Nicolas Carr, Sage Guyton, Jeremy Wakefield ["Three!"]
• Tension Times Two - Nicolas Carr [SpongeBob and Patrick scream]
• Sponge Monger - Sage Guyton, Jeremy Wakefield [SpongeBob and Patrick digging while being chased by Squidward]
• Steel Licks 6 - Jeremy Wakefield [Chum Bucket sinks underground]
‣ Scherzo Phrenia - Gregor F. Narholz ["Must dig!"]
• Steel Licks 3 - Jeremy Wakefield ["We're sorry!"/entire town sinks underground]
• Earl's Revenge - Sage Guyton, Jeremy Wakefield [ending]
- This episode is available on the Complete Seventh Season, Sunđer Bob Kockalone DVD 7, SpongeBob SquarePants Vol. 11, The SpongeBob SquarePants Collection, The SpongeBob SquarePants 8 Season DVD Collection, The Best 200 Episodes Ever, Bikini Bottom Buddies, and Next 100 Episodes DVDs.
- It is also a bonus feature on the Fanboy and Chum Chum Comic Chaos DVD in Australia and Europe.
- This episode was nominated for an Emmy at the 2011 Primetime Emmy Award for Outstanding Short-format Animated Program.
- Squidward hates Gary, but he appears to be friendly to him in this episode since he greets him when he sees him. Gary also greets him back.
- Irony: When SpongeBob and Patrick wanted to be together, they could have gone behind Squidward's backyard instead of building a tunnel, as Squidward didn't draw a line in his backyard.
- The scene when Squidward look at the window seeing SpongeBob and Patrick running from his lawn became a popular meme.
- The tunnel that SpongeBob and Patrick dig spells out "Eat at Krusty Krab."
- The gelatin on Squidward's head melted as he became angry at Patrick's knock-knock joke.
- When SpongeBob and Patrick were trapped by the boulder and Squidward comes around the corner, it scared some younger viewers.
- "Reprobate" means "an unprincipled person".
- The Brazilian name of this episode is "No Fundo do Poço" (In the Bottom of the Well). This phrase is also an expression to a person with a problem.
- When the Krusty Krab sinks, Plankton is happy, but then the Chum Bucket also sinks. This is opposite of the scene in "Slide Whistle Stooges," where Squidward destroyed the Chum Bucket with a truck, Mr. Krabs is happy, then Squidward also destroyed the Krusty Krab.
- When Squidward forces SpongeBob and Patrick to dig out his house on the count of three, he threatens to "grind them into chum" if they don't. Chum is fish guts, and this is an underwater show, so he likely meant that he was going to murder them.
- This is the second time Squidward threatens to kill SpongeBob. The first was "The Lost Mattress."
- In Bahasa Indonesia version, the final scene featuring Bikini Bottomites digging out Bikini Bottom was sometimes cut for unknown reasons.
- It takes much longer than just a count of three to dig out someone's house in real life.
- In airing order, this is the first episode to use the track "Light Conversation 1".
- The title of this episode is a reference to the phrase "sinking feeling."
- The underground chase is a reference to the arcade game Dig Dug.
- The sinking town may be a reference to the 1969 movie Paint Your Wagon, which also features a town sinking due to tunnels being dug beneath it.
- It would be nearly impossible for Squidward to hear SpongeBob and Patrick playing underground, as the earth would muffle out too much of the noise.
- When Squidward draws the lines, they are perfectly visible. However, when Squidward comes out, they are missing.
- Technically, Bikini Bottom has no need to get out of the ground, there are tunnels that lead to buildings.
- When SpongeBob and Patrick are "trapped" by the boulder, they try to go through it, not around it.
- When Squidward's house sinks into the ground, the "eyes" aren't visible, and the roof hatch is the only above-ground visible object; but later, when Bikini Bottom is underground, there is a large, skylight-like hole around the roof hatch area, the roof hatch is visible underground, and the "eyes" are visible.
- When SpongeBob and Patrick are standing in front of the giant rock while Squidward is yelling at them, SpongeBob blinks his eyes but his corneas are still visible.
- When SpongeBob and Patrick throw their pickaxes into the air, SpongeBob's sleeve turns transparent for a couple of frames.
- Plankton said that the Chum Bucket was the only restaurant in the city when the Krusty Krab was buried, but Diner and Fancy! are also restaurants located in Bikini Bottom.
- The roof hatch on top of Squidward doesn't appear at the end of the episode.
- Squidward's house sank slowly. The rest of the buildings sank nearly instantly.
- When Patrick first meets SpongeBob underground, his outline is black rather than pink.
- At one point, SpongeBob is missing his right arm.