At the Krusty Krab, Mr. Krabs announces that it is the 25th anniversary of the first time Plankton attempted to steal his secret recipe. Suddenly, a robot enters the restaurant, and Mr. Krabs pushes his employees aside, saying that he will handle this one. However, the robot orders chili coral bits instead of a Krabby Patty, it pays for them and leaves. Mr. Krabs is surprised that the robot wasn't Plankton, but Plankton then suddenly jumps out of the dollar bill the robot gave him. However, Plankton hadn't planned what to do next, not thinking he'd get this far, and is simply flushed down the toilet by Mr. Krabs.
He returns to the Chum Bucket, sulking to his computer wife, Karen about his failures. She then suggests to hire some henchmen to help him. He first goes to the Salty Spittoon, but the thugs beat him up. He then realizes that he has thousands of inbred relatives across the sea, and invites them all to come to the Chum Bucket, thinking they will all be evil geniuses like himself. However, when they arrive, he finds out they are all inbred rednecks, and comments that he's "been away from home longer than (he) thought."
He calls them to a meeting and gets them to agree to his plan in exchange for root beer. Plankton's first name is revealed to be Sheldon, which Karen finds hysterical and mocks his name. Plankton's army then attacks the Krusty Krab, tying up Mr. Krabs and Squidward in a toilet. The Planktons open the safe containing the Krabby Patty secret recipe. Before Plankton reads the recipe, Mr. Krabs pleads him not to read it, saying "There some things this world weren't meant to be seen by mortal eyes!" Plankton reads it anyway. The ingredients turn out to be:
A pinch of salt
3 tsp. of chopped onions
A cup of love
4 lb of freshly ground Plankton
Mr. Krabs says he warned him. Plankton is horrified by this, and runs away. The other plankton read it and run (except for Clem, who can't read, but Mr. Krabs orders him to get out). Mr. Krabs and Squidward manage to escape from the toilet, and SpongeBob returns from his task, and asks what happened. Squidward asks if a Krabby Patty is actually made of plankton, Mr. Krabs explains that the recipe that Plankton read is fake, and the real one is hidden somewhere "No one, not even Plankton, would ever figure out." Squidward then guesses that it is under Mr. Krabs' mattress, and Mr. Krabs runs to his house, yelling "Curse you, Squidward!"
SpongeBob only appears in two scenes: one at the very beginning and the other at the very end. This makes the episode to be one of the smallest appearances of SpongeBob in an episode ever to be aired, similar to "Rise and Shine" and "New Leaf."
It is revealed that Plankton's full name is "Sheldon J. Plankton."
Plankton's family shows much resemblance to the Trench Billies because of their lifestyle and appearance.
It should be noted that when Plankton was talking about how many other Planktons Mr. Krabs could handle, he was saying the number used in the power of ten in scientific notation.
When it originally aired, this episode was shown before "Missing Identity" due to being advertised as a "special" episode.
This episode wasn't mentioned in Comcast cable guides; only "Missing Identity" was.
Plankton says that "United, the Plankton family could be a real pain in the fanny!" However, closed captions say "belly" instead of "fanny." Though this may be because in the UK, the term "fanny" is a curse word.
Before it aired, many people mistook this episode to be a special or even a movie due to the nature of its advertisements.
For unknown reasons, some television guides say the episode was aired in 2002. Dish Networks original broadcast also set the episode to be aired in 2002 but changed to its correct date.
The robot who purchases the Coral Bits has a revolving light over its "eyes," much like the Cylons from Battlestar Galactica.
Plankton's past attempts at stealing the formula shown in this episode include:
Asking nicely. Mr. Krabs said no.
Wearing a cockroach costume; Mr. Krabs stepped on him.
Drinking a potion that turned him into a cockroach; Mr. Krabs stepped on him.
Protesting to Krabs that he is not a cockroach on a picket sign ("civil disobedience"); Krabs stepped on him again. One line from this episode can be heard in "Krusty Krab Training Video."
Plankton's snare drumroll that he performed sounded exactly the same that it was heard in "Wet Painters " and "The Fry Cook Games." Future episodes such as "Krabby Land" use exactly the same snare drumroll.
"Billy Billy Bo Billy Banana Fanna Fo Filly" is similar to a song called "The Name Game."
In this episode is one of the rare occasions where Plankton is squashed under his wife, Karen (under her robotic hand).
It's possible that this episode supports United Plankton Pictures, Inc., due to the picture of a Plankton (that looks like Plankton) holding hands with his cousins.
Running gag: Karen showing on her screen "SHELDON."
It turns out that Mr. Krabs hides the Secret Formula in his mattress just like he hides his money.
Instead saying he can't read, Clem said "For what?" in Indonesia.
In Mr. Krabs' office the walls were made out of wood, but when Mr. Krabs said, "I warned ya," the walls changed.
When Mr. Krabs said "Today is the 25th anniversary of the first time my arch rival, Plankton, ever tried to steal me secret Krabby Patty formula," the door to Mr. Krabs' office was shown, but when the robot showed up, the door was gone, and when Mr. Krabs and Squidward walked outside, the door was back.
When Plankton ran from the Krusty Krab back to the Chum Bucket, the road is much more curved and longer than usual.
Plankton is horrified that the fake recipe calls for ground-up plankton. This is ironic since chum is ground-up fish, and that's what Plankton's been serving his customers (most of whom are fish).
SpongeBob isn't victimized by swarm of Planktons that take over the Krusty Krab completely.
Outside the Krusty Krab there are millions of Planktons surrounding the restaurant, but after Plankton retreats to the Chum Bucket, there are fewer of them.
After Plankton got flushed from the Krusty Krab, he came out of the manhole directly between the Chum Bucket and the Krusty Krab. This is the only time this manhole is seen.
In this episode, Mr. Krabs claims that Plankton has been trying to steal the formula for 25 years; however, in "Spy Buddies" (which aired three years after this episode), he claims that Plankton has been trying to steal it for 20 years. It's possible that "Spy Buddies" took place before "Plankton's Army."
When the robot shows up at the Krusty Krab the Chum Bucket is missing.
When Plankton says "Who will join me!", his mouth is out of sync.