"Jeffy's Cat Piano Problem!" is the 332nd episode of SML Movies.
Jeffy gets his cat piano and starts singing a song about diarrhea. However, Mario doesn't like it and takes Jeffy's cat piano away. Mario grounds Jeffy and says he can't get his cat piano back for a month.
Jeffy has a temper tantrum and throws Junior's toys. Junior asks what's wrong and Jeffy said his dad took his Cat Piano so they went searching but they were unable to find it. Junior ask Jeffy to ask Mario for a hint but Mario wouldn't give any hints, so Junior gave Jeffy a mini mushroom. He explains that he will become small using a mini mushroom and he would spitball him inside of Mario's head.
Junior then spitball him into Mario's head. When Jeffy gets inside the head he starts controlling Mario to act like him. Mario tells Rosalina to call the cop and Rosalina questions what's wrong with Mario. Mario did ridiculous stuff that Jeffy does like cussing and hating green beans. He also dance the Hop Hop and yelled "Uh Uh" out loud.
Then, in the kitchen Rosalina gives him green beans to eat. But Mario has lost control of his own mind so now he's completely acting like Jeffy. Mario was shown wearing a diaper. Mario then throws the green beans all over the table and asks for the cat piano. Mario then gets the cat piano and sneezes Jeffy out of his head. Mario recovers and doesn't remember what happened. Mario saw Jeffy with the Cat Piano and yelled to give it back but Rosalina yells at Mario and defends Jeffy by saying he can't take a trade back. Jeffy sings the diarrhea song and poops his pants and the video ends.
- This episode reveals that Mario's favorite vegetable is green beans which is probably the reason he makes Jeffy eat them.
- This episode also reveals that Jeffy still hates green beans and that he broke his promise that he would eat them.
- It is possible he still hates green beans, but he still eats them doesn't express his hatred of green beans to Mario and Rosalina like he used to.
- There is probably no doubt that Jeffy now knows Mario likes green beans, which is probably why Mario tries to feed them to him. It is possible that Jeffy will probably confront Mario about this in the future.
- This episode is probably also Jeffy's act of payback on Mario for him trying to feed green beans to Jeffy in Jeffy and the Beanstalk!.
- This episode is similar to the SpongeBob episode “Plankton” where one character goes in another's brain and controls the other person. It is also similar to the Dragon Tales episode "Flip Flop" where Zak and Wheezie change personalities.
- The diarrhea song actually originates from Bob's Burgers.
- The Mini Mushroom from Shrek's Bath Problem! and Jeffy Gets Stung By a Bee! returns.
- The green bean joke returns after Jeffy promised to eat them in Jeffy and the Beanstalk!, However, it is possible that Jeffy controlled Mario, so he won't turn into a green bean.
- It's also possible that after this, Rosalina won't buy green beans anymore. Nor will Mario try and feed them to Jeffy.
- The plot was once leaked in the Discord server of this wiki when users Konanoki and NotNickelodeon showed screenshots of Chilly leaking the plot in Instagram private messages.
- Jeffy's thumbnail pose from Jeffy's Home Alone! is used in this video.
- This video reached at most, #10 on YouTube Trending.
- This is the third time that Mario plays on Cat Piano. The first being Jeffy's Homework! and the second being Jeffy's Parents!
- This is the first time Mario dances to The Bunny Do. However, this is only when he was being controlled by Jeffy. However, he also sings it in Jeffy Sneaks Out! to tell which Jeffy was which.
- It is unknown why the emotions (from Inside Jeffy) inside Mario's brain are not seen in this video. It is likely that Jeffy did not reach the area where Mario's Emotions are in.