Starlight realised about the enchanted mirror that will lead them to Canterlot High. When she saw that Sunset Shimmer is taking care of Flurry Heart, she thought that she kidnapped her. She gathered all of Equestria and told them about Sunset thinking that she became a traitor. All of the ponies, except Twilight, Rarity, Rainbow Dash, Applejack, Pinkie Pie, Fluttershy, Spike, Shinging Armor, Cadence, Celestia, and Luna, agreed with Starlight and became an angry mob.
 
Starlight Glimmer: (Angrily) Sunset abandoned us and began living in the human world! She had maked off with Flurry Heart! She kidnapped her for her own! If we let these two legged creatures, they will destroy all we have worked for and steal all of Equestria! Will we let Sunset get away with this?!
 
The angry mob: (Angrily) NOOOO!!
 
Starlight: Then Let us travel through the mirror together and steal the baby princess back! We won’t be safe until Sunset and the humans are dead, I say we kill them all!!
 
Twilight: No! Starlight, Sunset’s not a monster, she’s reformed and she didn’t really kidnap my niece.
 
Spike: That’s right! We’ve saw who she became now!
 
Starlight Glimmer: The traitor has Twilight and Spike under a spell! If I didn’t know better I say they cared for her! We can’t have them running off to warn the two legged creatures! Lock them away! Who’s with me?!
 
Everypony: I am! I am!
 
Trixie: I am!
 
Discord: I am!
 
The Cutie Mark Crusaders: We are!
 
That is when they all form an angry mob and sang the mob song (the Mob song from Beauty and the Beast)