This story is a sequel to My Enemy's Enemy
Rainbow Dash is staying in Canterlot for a few days to perform in a Wonderbolts show, and she decides to take Scootaloo with her. Scootaloo finds herself becoming a celebrity of sorts at Central Canterlot School and begins basking in her new-found glory - but she soon notices a young changeling, Pupa, is being left out and tormented by the other students. Will Scootaloo be forced to put her popularity aside to help a filly in need?
(The prequel isn't necessary reading, all you need to know is changelings and ponies aren't enemies anymore, and the changelings live in Canterlot now, alongside the ponies :3)