In the beginning at Shady Shoals Rest Home, Plankton is with his grandmother, who is lying down on a bed. After thinking of what to do with her, Plankton puts his grandmother to sleep, and then takes some of her clothes to wear.
Plankton later walks over to SpongeBob's house, where he appears. Plankton says that he is his great grandmother, in which he actually believes so. SpongeBob gives his "great grandmother" a tour of his house and shows Plankton all of his albums. The next day, Plankton wants to go to the Krusty Krab, but SpongeBob insists that they go to a nursing home instead. There, they knit and play cards, when Plankton rips a card in annoyance at SpongeBob's antics.
SpongeBob realizes he is bored and decides to take him to the Krusty Krab, although Plankton says he wants to enter through the back door.
Meanwhile, Plankton ties up a balloon that looks like him. It flies away into the dishwasher, and when SpongeBob turns it on, the balloon pops. SpongeBob, thinking it is his great grandma, cries, but then Plankton re-appears and says he is fine. After, Plankton tells SpongeBob that he is tired and needs to take a nap in a private place. SpongeBob agrees and takes him to the safe. Thereafter, Plankton's grandma walks inside of the Krusty Krab and finds out what Plankton is secretly plotting. She takes him back while SpongeBob thinks that his own great grandma caught Plankton trying to steal the formula.
Towards the beginning of the episode during Plankton's fantasy, when he tells Mr. Krabs he needs to take the recipe home because he "forgot" his bifocals, he is actually wearing them.
This episode says that when SpongeBob was a baby, he was a yellow blob, but in several other episodes (such as "Goo Goo Gas" and "Friend or Foe"), he's just smaller as a baby kitchen sponge.
Also in "Truth or Square," he is still seen in sponge form even inside the womb.
When Gramma Plankton gets her dress back from Plankton, he covers his legs, even though he is always shown like that since his debut appearance. However, this might be for comical effect.
When Plankton pulls down his antennae, they are quickly stuck back up when SpongeBob and Plankton are walking together.
Gramma Plankton calls her grandson "Plankton," but actually, she should be calling him "Sheldon" - "Plankton" is the family name.
Irony: It would have made more sense for Plankton to steal the formula himself (like in his vision) than to pretend to be SpongeBob's grandma.
Plankton said when he discovered his "nightmare" was true "Holy Mother of Neptune it's true." SpongeBob said a similar line in "Gone," when he said, "So it was true…"
This episode premiered on Burt Ward's 65th birthday.
While SpongeBob was taking a bath, he had no clothes. Suddenly, Great Grammie Ma Plankton knocked on SpongeBob's door. Then, in the next shot, SpongeBob had his clothes on when he got wet.
When Plankton is turned into a scarf, he has two eyes.
There was chocolate on the pillow and blanket but when Plankton was laughing, it was gone.
When Squidward dumps the trash, the shape of the sack doesn't change.
After Plankton steals his grandma's clothes and hair, she still has hair, but at the end, she is bald when she comes to take it back. The error was later fixed in re-runs and on the Season 7 DVD release.
However, this is unfixed in some countries, as like Israel, Croatia and Germany.
Whenever Plankton took off the glasses, his one eye disappears when he puts them back on and off.
The balloon "Grammie Ma" should have popped when it went in the garbage disposal, but was slowly cut up.
When Spongebob and Plankton are playing cards, the animation cell for the table in the background is above Spongebob's, so parts of his left hand are erased multiple times when it goes near the table