At Beacon, classes had ended and Twilight was walking with Star. 

Twilight: Okay Star, it's time to get back to- 

She then noticed a little purple heart on the middle of her forehead. 

Twilight: You have some ... paint ... on your forehead. 

Star: Twi, this is not paint. 

The heart was peeled off. 

Twilight: Right ... I- AGH! 

She noticed another one appear. 

Twilight: There's another. 

Star: Another? 

She looked in the mirror and pulled Twilight aside. 

Star: Twilight, listen to me. This is serious! I think I'm going through .. mewberty. 

More hearts appeared on her face, and she pulled her hair over her face. 

Twilight: Mewberty? HAHAHAHAHAHA! Star, calm down. Humans go through something like this too. I read about it myself. It's called puberty. It's completely normal. 

Star: Don't confuse this with something else! I'm from Mewni! This is going to get really weird. You have to keep me away from boys! Especially (Y/N)! 

Twilight: Wait ... do you have feelings for him? 

Star: Well ... I- 

She blushed. 

Star: M-Maybe ... I just- 

She then saw a guy pass by. 

Star: BOY! 

Twilight: OH NO YOU DON'T! 

Twilight used her magic to stop Star. And while Star may have powerful magic, Twilight's was stronger. 

Twilight: Now, when you say things are weird, do you mean your type of weird, or destruction weird? 

Star: The latter. 

Twilight: That's what I was afraid of. Look, let's just head home. 

Twilight starts dragging Star back home, but then she sees another boy. 

Star: (whispering) Oh-no-oh-no-oh-no. Okay, here comes a boy. You got this. You got this. Avert your eyes. Avert your eyes.

More hearts appeared on her face. 

Star: Twilight, this was not a good idea! 

Star ended up breaking free from Twilight's control and went up to watch the boy drinking from a water bottle. 

Twilight: Okay, come on. 

She held her arm tightly and dragged her off. 

Suddenly Star shot out a purple web from her hand, which sticks to a locker. 

Twilight and Star: AAAAAAAAAAAAAAAAAAAAAAAAAAAGH! 

Twilight let go of Star's arm, which had now turned purple. 

Star tries to unstick herself from the locker, and it swings open. 

Star then fell over and slid halfway into the locker. 

Star: AGH! I'm STUCK! 

Twilight: Hang on Star, I- 

Star: NO! You need to find way to stop this! 

Twilight: What do you want me to do? I don't know anything about Mewni Magic! 

Star: Look for my Book of Spells! It's in my room at home! 

Twilight: Right! I'll be right back! 

As Twilight took off, a bunch of purple hearts fell out of the vent in the locker and onto a pile of purple hearts. 

Star is peeling all the hearts that appear on her. 

Star: (sigh) That's much better. 

Then she saw more of the students of Beacon coming by and chatting. 

Star: NO NO NO NO NO NO! 

More purple hearts appeared on her face, and on her arms. 

Star: NO NO NO NO NO NO NO NO NO NO NO NO NO NO NO! 

Soon... 

Twilight had got you and Sunset along with the Book of Spells. 

(Y/N): Mewberty? 

Sunset: Is this another Mewni thing? That hydra thing was way out of control. 

Twilight: I know. But come on, I need both of your help. 

Sunset: Twilight, we don't know anything about Mewni Magic. 

Twilight: Well neither do I! But there has to be something that we can use here to help us! 

(Y/N): In this big book? Hmm ... 

You looked through the Book of Spells. 

(Y/N): No! 

You looked again. 

(Y/N): NO! 

And again. 

(Y/N): ARGH! NO! 

It seemed like you were getting nowhere. 

(Y/N): HOW DOES THIS STINKING BOOK WORK!? 

Twilight: (Y/N), easy there. 

Sunset: We'll just need to find the glossary. That is if there is one. 

Suddenly the book's pages flipped by themselves and- 

???: Did someone mention Glossaryck? 

Out from the pages appeared a little man. 

Glossaryck (The Living Embodiment of the Book of Spells! He was the aide for Moon and all the other previous queens! While wise, he is also a smartass and snarky! Has a love for pudding! Voiced by Jeffery Tambor!) 

(Y/N): What? Who are you? 

Glossarcuk: I am Sir Glossaruck. Of Terms. At your service, Milady. 

(Y/N): I'm not a lady. 

Glossaryck: ... Could have fooled me. Goodbye. 

He closed the book. 

Twilight and Sunset: NO! WAIT! 

Glossaryck: The book is not for the likes of any of you. Oly for magical princesses! 

Twilight: I am a princess! 

Glossaryck: Oh no no no no. I mean princesses of Mewni. 

Sunset: Oh no, he's one of those types. 

(Y/N): Yeah ... a smartass. 

Twilight: Look, we're doing this for Star! 

Glossaryck: Oh! HAHAHAHAHA! Star Butterfly. What's up with her? 

(Y/N), Twilight, and Sunset: She's going through mewberty. 

Glossaryck: Well, I don't usually make exceptions, but I think we can work something out. Pudding. 

Sunset: P-Pudding? 

Glossaryck: I want pudding. 

(Y/N): Right. To the kitchen!

Twilight: Are we seriously just going to- 

(Y/N): Look, we need to get this weirdo his pudding. He knows what Star's going through. So we need his advice. 

Sunset: (Y/N) is right Twilight. Besides, time is of the essence. 

Twilight: Right, let's go. 

Back at the locker... 

We see a certain blonde Demon Slayer thinking about well- 

Zenitsu: Man ... the girls looked really cute in their gym uniforms. I wish that new girl showed up. She's really cute! 

Then he noticed something nearby.

Zenitsu: AAAAAAAAAAAAGH! WHAT IS THAT?! 

A giant cocoon of purple hearts was where the locker should be. 

Star: Boy ... Booooy. 

Star's face came out, and the cocoon unravele to reveal-

Zenitsu: Uh ... okay. Just work through with this Zenitsu. (charmingly) Why hello there, Ms., you look very cute to-

Star: BOY! 

She trapped him in a bunch of webs! 

Zenitsu: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARGH! SOMEONE HELP ME! I'M BEING KIDNAPPED AGAINST MY WILL! THIS IS NOT HOW I WANT A FIRST DATE TO GO! SOMEBODY! TANJIRO! (Y/N)! I'll even take Inosuke! 

He was shoved into the locker as Star smiled. 

Star: Boy!