Scootaloo's Cutie Mark

Epilogue
Rainbow Dash was flying through the sky, practicing her Buccaneer Blitz move, when suddenly, a small orange blur whizzed by her, throwing her off track. Immediately proceeding this, there was the boom of the sound barrier being broken, and a rainbow appeared in a line.
Dash smiled, thinking to herself how now she has a rival.
Then, another, louder boom sounded, and the rainbow trail became doubled. Dash rubbed her eyes, and looked on in astonishment. She looked on as the small orange blur she knew to be Scootaloo left in her wake dual rainbows. Then, Scootaloo stopped midflight, attempting to push through another layer of the sound barrier, but physics wouldn't allow it. Scootaloo fainted, and began to fall. Rainbow Dash, knowing she had to move, pulled her own Sonic Rainboom to get over to Scootaloo in time to save her.
Moments later, after both pegasi touched ground, Scootaloo awoke from her sleep, and looked into the sky to see her rainbow still remained, and how Rainbow Dash's rainbow began to fade...
Scoots sleepily remarked "It's so bright, Rainbow. It's so...vivid. Look at the double rainbow. With yours there, it's starting to even look like a triple rainbow. But yours is fading. What does it mean?"
Rainbow Dash said, "It means the student has become the master."

The true end.