| Please note the following:
"Jeffy's Favorite Song!" is the 242nd video of SML Movies.
Jeffy hears a new song and falls in love with it.
Mario and Rosalina are putting together a 1,000 piece puzzle in the living room when Jeffy comes into the room and starts to annoy Mario with stupid (and disgusting) questions. Finally, Mario throws the remote at Jeffy and tells him to watch TV. When Jeffy turns the TV on, there is a miscellaneous children's TV show on that begins to play a song called "Hop Hop", which Jeffy and Rosalina immediately become addicted to, however, Mario instantly becomes annoyed with it and turns the TV off before the song begins.
After Rosalina begs Mario to turn the TV back on, Mario, reluctantly, does. When the song ends on the TV, Jeffy again becomes devastated and wants to keep listening to it. Mario is overjoyed that the song is finally over but, much to his dismay, Rosalina finds it on Jeffy's phone via iTunes. Unable to take it any longer, Mario grabs Jeffy's phone and destroys it with a hammer. However, Rosalina tells Mario that she will play is repeatedly on her phone until Mario buys Jeffy a new phone, since he just broke his old one.
Mario caves and goes to the store to buy Jeffy the iPhone 7. When he gets home, he vows that Jeffy only be allowed to use it if he uses ear-buds, so that he won't annoy Mario anymore with the song. However, Mario finds, much to his horror, that the headphone jack is missing on the iPhone 7 (an obvious satire of the controversial design of the phone, which omits the headphone jack). As a result, Mario is now stuck listening to Jeffy's annoying song.
Jeffy continues listening to the song for the next several hours until midnight, when Mario makes Jeffy turn the song off and go to bed. However, Jeffy, who has gone to bed in a rabbit suit, tells Mario that he refuses to go to sleep unless he listens to the song seven more times (originally five and six).
Finally, Jeffy goes to sleep, and Mario thinks that he is in complete peace. However, the bedroom door opens and in comes a humongous rabbit, similar to the one featured in the music video of the annoying song, only much bigger, having a deeper voice and being far more terrifying. The rabbit comes in singing the same song, but with a deeper voice. The rabbit grabs Mario and eats his head.
- This is the fifth time Jeffy doesn't spank his diaper at all, the first was Jeffy Gets Potty Trained!, the second being Jeffy's Cellphone!, the third being Bowser Junior's Game Night 4, and the fourth being Jeffy's Mistake!
- This is the 1st time Jeffy jumps.
- This might be the 11th time Mario dies. However, it is possible that the rabbit scene where Mario is eaten was only a dream: if so, Mario theoretically didn't die at all. The reason why Jeffy and Rosalina did not die is because they like the bunny.
- The full version of "The Bunny Do!" can be found on SuperLuigiLogan, as stated in the description and is called "The Bunny Do!".
- The answer to Jeffy's question, "What would happen if a girl poops on the glass and it smears up her back?" is that most likely she'll get dirty and will have to take a shower.
- Jeffy might have summoned the bunny in an act of evilness if the final scene was real.
- It is appropriate that the bunny came in the room at 3 a.m., because 3 a.m. is commonly known as The Devil's Hour.
- As of December 2017, this video got age-restricted due to the scary hop hop bunny walking towards Mario and eats his head but it's not anymore.
- Originally, the video was going to end with Nightmare Hop Hop Bunny singing the song to Mario, followed by him getting addicted to it while Jeffy and Rosalina don't like it anymore, but this was cut due to time constraints.
- Mario smashing Jeffy's phone with a hammer is possibly inspired by YouTube user TechRax, who usually focuses on destroying technology.
- At 6:43, Jeffy says he needs to listen to the song 5 more times, but holds up only 4 fingers. This is because the Jeffy puppet is made to have only 4 fingers.
- Jeffy surprisingly didn't scream or cry when Mario threw the remote and it hit his face, this could've been an accident.
- When Jeffy listens to the song at night, the light is on. However, the light goes off when the next scene is played. It could possibly be Bowser or Chef Pee Pee, or even Mario, but it is unknown.
- Mario said that he was going to break up with Rosalina if she played the song again and when she did play the song anyway, he didn't break up with her. It's possible he was just saying that or he changed his mind and felt too guilty to break up with her for real, or it was an empty threat.
- While Jeffy and Rosalina were listening to the song, it is unknown why didn't Mario leave the room if the song was too annoying for him.
- Mario should have gave Jeffy headphones before smashing his old phone even if he still didn't know that the iPhone 7 doesn't have a headphone jack.
- Even though Jeffy's phone didn't have a headphone jack, they still could've plugged the headphones into Rosalina's phone, she even said that she had a headphone jack. It's possible that Mario and Rosalina quickly forgot about that or didn't think of that.
- Even if the iPhone 7 does not have a headphone jack, Mario could have used the lightning headphones that came with it.