- SpongeBob SquarePants
- Patrick Star
- Sea Whelks (debut)
- Mother Sea Whelk (debut)
- Abigail Marge
- Frankie Billy
- Jimmy Gus
- Nancy Suzy Fish
- Frank the Red-Shirt-Wearing Fish
- Debbie Rechid
- Nathiel Waters
- Johnny Elaine
- Gary the Snail (cameo)
- Squidward Tentacles
- Nat Peterson
- Harold "Bill" Reginald
- Fred (blue)
- Eugene H. Krabs
- Medley Fishbowl
- Sandy Cheeks
- Margaret SquarePants (mentioned)
- Frank the Lifeguard
- Shelly Fishbowl
SynopsisSpongeBob and Patrick are in Jellyfish Fields when they hear a strange noise. Soon, a stampede of large whelks make their way through Jellyfish Fields, destroying anything in their path, including SpongeBob and Patrick. The whelks covered them in purple goo, and proceeded. As the whelks made their way to Bikini Bottom, SpongeBob and Patrick decide to warn the Bikini Bottomites about the whelks, but too late. Back in Bikini Bottom, the whelks were chasing and terrorizing everyone. They would blow purple goo bubbles around their victims and swallow the bubbles with their victims inside. SpongeBob and Patrick were asking who are those monsters. But Patrick was never scared of them. Johnny Elaine explains them on TV, suddenly he signs off the news when he also has been eaten by a sea whelk. When SpongeBob and Patrick got to the Krusty Krab, they warn Mr. Krabs about the coming danger. Soon after, the whelks make their way to the Krusty Krab, but Mr. Krabs thinks they are just plain old customers.
A larger mother whelk is then revealed, assisting her "babies." When he offered them all a Krabby Patty, the mother swallowed him, along with Squidward and the entire Krusty Krab. SpongeBob and Patrick then ran to Sandy's treedome, where after being tested that they were SpongeBob and Patrick and not the whelks, they went inside. Sandy put metal armor around the Treedome for protection against the whelks and told SpongeBob and Patrick her plan to defeat the whelks.Suddenly, the whelks crack and destroy the Treedome and SpongeBob, Sandy, and Patrick are swallowed by the mother whelk. Inside the whelk, Sandy discovered that the whelks were sick, or "had the sniffles." SpongeBob then simply helped the whelk get better again by doing what he did to cure his suds, revealing the whelk's true form, a tiny, helpless whelk. SpongeBob does this to all the whelks and restored the whelks' happy family. All of the "eaten" victims were rescued, and the episode ends with Squidward complaining about all that just because the whelks "had the sniffles," then getting doused with purple whelk goo.
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ The Creature (a) - Gregor F. Narholz [title card]
‣ Aloha Eo - Nicolas Carr, Sage Guyton, Jeremy Wakefield [opening]
‣ Earl's Revenge - Sage Guyton, Jeremy Wakefield [SpongeBob, Patrick jellyfishing]
‣ Monster Bug (a) - Gregor F. Narholz [rumbling]
‣ Lite Conversation - Nicolas Carr, Barry Anthony [SpongeBob and Patrick covered in slime]
‣ Fight for Your Life! - Gregor F. Narholz [whelks invading Bikini Bottom]
‣ Bikini Bottom News Theme - Nicolas Carr [news on TV]
‣ Drama Link (d) - Hubert Clifford [SpongeBob screams]
‣ Steel Sting - Jeremy Wakefield ["Hey, Gary."]
‣ Cartoon Sting 2 - Patrick teases a whelk
‣ The Creature (a) - Gregor F. Narholz [whelk roars at Patrick/Patrick runs off]
‣ Attack - Tony Hymas [SpongeBob warning Krabs about the whelks]
‣ Harp Ding - Nicolas Carr ["That means hungry!"]
‣ Monster Bug (a) - Gregor F. Narholz [whelks approaching Krusty Krab]
‣ Sailor's Sting 4 - Michael Bolger, Nicolas Carr ["Krabby Patties! Get your Krabby Patties!"]
‣ Monster Bug (a) - Gregor F. Narholz [giant mother whelk appears]
‣ The Creature (a) - Gregor F. Narholz [mother whelk eats Krusty Krab]
‣ Attack of the Giant Robots - Cris Velasco [Sandy lets SpongeBob and Patrick in]
‣ The Creature (b) - Gregor F. Narholz ["What are we gonna do?"]
‣ Retro Cool 03 095 D - Steve Sechi [action-packed answer]
‣ Fight the Beast! - Gregor F. Narholz [whelks invade treedome]
‣ Command Post 2 - Harry Bluestone, Emil Cadkin ["Follow me!"]
‣ Death Throws - Harry Bluestone, Emil Cadkin ["I guess this is it, Patrick."]
‣ Fight the Beast! - Gregor F. Narholz [mother whelk eats Sandy]
‣ Desperate Situation - Phil Green [SpongeBob and Patrick inside the whelk's stomach]
‣ Fighting Legions (a) - Gregor F. Narholz ["The Krusty Krab!"]
‣ Vibe Q Sting - Nicolas Carr ["Hmm..."]
‣ Sneaking About - Phil Green [SpongeBob and Patrick lend Sandy their corneas]
‣ Lonely Stranger - Laurie Johnson [Sandy examining the whelks' slime under a microscope]
‣ Steel Link (c) - Jeremy Wakefield ["I know just what to do!"]
‣ Lionheart - Larry Hochman [SpongeBob absorbing the whelks' snot]
‣ Lap Steel - Nicolas Carr [SpongeBob laughs]
‣ Wahini Wobble - Nicolas Carr, Sage Guyton, Jeremy Wakefield [ending]
- As of August 19, 2016, The Internet Movie Database (IMDB) gives this episode a rating of 7.6/10 based on 73 ratings by users. TV.com users give this episode a rating of 7.5/10 based on 81 votes.
- It is revealed that SpongeBob's mother's maiden name is "BubbleBottom."
- Even though the episode focuses mainly on the whelks, there appear to be urchins on the title card.
- In this episode, to put a metal shield over her treedome, Sandy presses a button on her tree, but in "Texas" it was a lever.
- The metal sheeting also goes much slower in this episode rather than in "Texas."
- SpongeBob refers to the episode "Suds" when he says "After all, I've had the suds."
- This episode premiered 11 years after the premiere of "The Chaperone" and "Employee of the Month."
- This episode reveals that at least SpongeBob's water helmet is a replacement helmet for Sandy.
- When the whelks appear, one eats Dale, but earlier, when SpongeBob goes in the Krusty Krab, Dale is in the Krusty Krab.
- When Sandy lets in SpongeBob and Patrick, she's wearing her spacesuit, but when they're all in her treedome, Sandy is in her bikini.
- When Sandy uses SpongeBob's helmet, it does not have a flower on the top, but when Sandy is at the Krusty Krab, in the Sea Whelk's stomach, the helmet does have a flower.
- During the time when Sandy uses SpongeBob's helmet, Patrick is still wearing his helmet, but when they land, Patrick's helmet disappears.
- When the tower is raising from the Krusty Krab, in one frame, SpongeBob has his uniform hat on; while in the previous and following frame, he does not.