The episode starts at a normal day at the Krusty Krab. Mr. Krabs is doing paperwork and is confused as to why his profits are down. He goes out into the restaurant to see Squidward making a sale, minus the price of a drink. Mr. Krabs sees everyone is drinking a thing in a bottle, including SpongeBob. He tells Mr. Krabs about the drink called the "Kelpshake." Mr. Krabs worries that people aren't buying drinks with their food, so he bans outside drinks in his restaurant, forcing the customers to leave.
He goes to see what Plankton has done this time. He doesn't know Plankton isn't behind this. Plankton tells Mr. Krabs he has no idea what is going on because he was relaxing in a beach chair. Then the two try to steal a Kelpshake and discover what it is made of. They go to a Kelpshake stand and try to get Plankton to find out, and all attempts fail. That night they both try to enter but an alarm wakes up a guard worm who attacks them. The next day Mr. Krabs reluctantly buys a Kelpshake and goes to the Chum Bucket to analyze what is made of.
Karen starts analyzing, but Plankton gets impatient and interrupts the progress of the analyzer. They find out that the drink has two ingredients, the primary one being kelp juice. The two drink the shake and find it to be delicious, but ignore Karen, who tries warning them about the other ingredient in the drink. After going out to buy some more kelp shakes, SpongeBob runs out of the Krusty Krab, wailing and crying. He is covered in green fuzz all over, and his clothes are gone. He also tells them that they're closing down the Kelp-Shake Restaurants and he runs away again. Then they go out and see that all Kelpshake restaurants are closed because their shakes contained a toxic and dangerous ingredient. Two decontaminants revealed that it will take decades to get rid of the unhealthy toxic waste and they're sorry for whoever drank the stuff. Then Mr. Krabs and Plankton grow the fuzz all over their body. So Plankton decides to go back to stealing The Krabby Patty formula and Mr. Krabs gives him a Krabby Patty and then chases him just for the fun of it.
At the part where Mr. Krabs sneezes, you can see the employee sign says "Employes Only." It is missing the third "e." Also, the sign was purple. But when Plankton landed, the sign was yellow.
On Nickelodeon UK when this episode aired on August 15, 2010, Mr. Krabs says: "Hey, haha haha haha!" while in other countries like the US, he says "Hey, get back here you little booger, Hahahahahahahaha!" to Plankton. This is because the word 'booger" sounds similar to "bugger" which is a word deemed profane in the UK, while in other English-speaking countries it is a nickname for a mischievous child.
The last time the Chum Bucket was shown, it was destroyed by the Kelp Shake building, but it was shown again later when Mr. Krabs and Plankton tried to analyze the ingredients.
The tannoy which warns Mr. Krabs and Plankton says You have three seconds before spontaneous combustion! and then pulls out a laser, but in real-life, spontaneous combustion means something that suddenly bursts into flames.
Mr. Krabs and Plankton would later work together again in "The Other Patty."
It is not known why SpongeBob was hanging around the Kelpshake Store at night.
The customer who just ordered a Krabby Patty only paid a dollar for it. This episode may have taken place on a Wednesday because according to SpongeBob back in the episode "Imitation Krabs," a single Krabby Patty only costs a dollar on Wednesdays.
In Greek, this episode is called Φικοσέικ which means Kelp-Shake.
When SpongeBob sucked the Kelpshake for the first time, the straw was outside his mouth.
After Mr. Krabs says Hey, get back here you little booger. Plankton disappears before the whole thing cut to blank.
There were three Kelp Shakes next to the Krusty Krab, two on the left and one on the right, but when SpongeBob was talking to Mr. Krabs and Plankton inside the Krusty Krab, two of Kelp Shakes on the left outside were gone.