25th day of August 2009, SpongeBob 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. Fish Head explains them on TV, suddenly he signs off the news when he also have been eaten by a sea whelk. When SpongeBob and Patrick got to the Krusty Krab, they warn Mr. Krabs about the coming danger. But soon, 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 the entire Krusty Krab. SpongeBob and Patrick then ran to Sandy 's treedome, where after being tested, 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 of 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 end with Squidward complaining about all that just because the whelks "had the sniffles," then getting doused with purple whelk goo.
It is revealed that SpongeBob's mother's maiden name is BubbleBottom.
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.
SpongeBob refers to the previous episode, "Suds", when he says "After all, I've had the suds".
The disease that transformed the sea whelks into monsters is possibly a mutated virus. It is unknown where the mutated virus came from.
When Sandy uses SpongeBob's helmet and put it on her space suit she flushes the water with a pull string attached to her spacesuit instead of using her flushing handle that was seen in Texas.
The sea whelks were been based on the Scarab beetles in the film The Mummy. When they were writing the script for this, they thought about The Lord of the Rings, where the goblins start climbing down the columns in the Mines of Moria.
When the whelks appear, one eats Dale, but earlier, when SpongeBob goes in the Krusty Krab, Dale is in the Krusty Krab.
When SpongeBob was trying to describe how big the whelks were to Mr. Krabs, he says: "They kinda look like Gary, but not really."
In the scene where they are watching the news report, Patrick was covered in slime. The next scene the slime is on the ground.
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.
Before SpongeBob and Patrick are running to the Krusty Krab, SpongeBob's right sleeve is green.
When Sandy uses SpongeBob's helmet, It does not have a flower on the top. But when Sandy was at the Krusty Krab, it 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.