The episode begins with a bubble with a letter inside flying to SpongeBob's house while causing mischievous antics. It finally flies into SpongeBob's kitchen, who is enjoying a bowl of Kelpo cereal with Gary. SpongeBob opens the letter, which is from his old friend, Bubble Buddy, asking him to babysit his son, Shiny. Shiny appears out of the bubble holding the letter. SpongeBob introduces himself and takes Shiny to meet Squidward. Unfortunately, Shiny causes mayhem in Squidward's house and SpongeBob cannot find him. Shiny keeps flying in Squidward's house and destroying furniture. SpongeBob is being careful so Shiny will not pop from all the sharp objects in Squidward's house.
Eventually, SpongeBob catches him and takes Shiny to the Krusty Krab. Then, he goes into Mr. Krabs' office and flies everywhere around him. Mr. Krabs is shiny and clean from the bubble soap and tells SpongeBob to let Shiny play in the dirty dishes. Then, while SpongeBob is cooking Krabby Patties, Shiny once again gets into mischief by sliding around, and making the Krusty Krab floors slippery. All the customers keep slipping, so Mr. Krabs kicks them out. Then, Shiny flies into the city and gets into lots of trouble.
He goes into the Bikini Bottom Pin Factory, Bikini Bottom Scissor Works, and the Pitchfork Pantry. Then, SpongeBob decides to go to the Bikini Bottom Pillow Foundry and he finds out that it is a dangerous place too. When they get home, he feeds Shiny a hot dog. But then he pops, and SpongeBob has the bubble soap to repair him. Finally, when he blows another Shiny, he grows two heads. Then, Bubble Buddy comes to his house to pick up Shiny. SpongeBob begins to apologize about Shiny, but Bubble Buddy says that it was okay, because sometimes, it had happened to Shiny. Then, he traps Shiny into a bottle of bubble soap. As they are leaving on a bubble plane, Shiny is normal again, blowing a raspberry out from the bottle and they go into the plane and fly away.
The bubble plane was first on the ground, but was lifted into the sky. The same thing happens to the taxi at the end of the episode "Bubble Buddy."
Shiny showed no signs of life until the end, just like his father in "Bubble Buddy."
In the letter from Bubble Buddy, it says "We don't want him to go pop like his late Uncle Raymond". This is the first mention of any relatives of Bubble Buddy. It's possible that Raymond is Shiny's maternal uncle because SpongeBob might not remember creating Raymond from bubble blowing.
Squidward painted his self-portrait to resemble Napoleon Bonaparte.
Mr. Krabs makes reference to Bubble Buddy's visit in "Bubble Buddy" and him not paying.
As seen in other episodes, bubbles in the SpongeBob SquarePants universe have properties more similar to inflated balloons than bubbles. For example, when Shiny was caught in the blades of Squidward's fan, he wasn't popped. Instead, he spun around them, the way a helium-filled balloon would if caught in the same situation.
Figuratively speaking, Shiny is SpongeBob's grandson because SpongeBob created Bubble Buddy and Shiny is Bubble Buddy's son.
Running Gag: Shiny floating into different sharp objects and factories, but doesn't pop while SpongeBob, who is trying to save him, ends up getting hurt.
In Bubble Buddy, Bubble Buddy drives an automobile home. In this episode, he rides an airplane home, stating he must have moved further away.
Despite Bubble Buddy's name in the title, he rarely appears in the episode.
This is Bubble Buddy's second appearance after 11 years.
Mr. Krabs was able to remember that Bubble Buddy still owes him money from "Bubble Buddy." This is the only use of legitimate continuity in the entire series.