The Rainboom

A couple of months later, Dash was sitting between his mother and Princess Twilight at a Wonderbolts show. They were told that this one would be extra special - what did Rainbow have planned?

“And now, for the finale!” the announcer said into the microphone. That’s my cue, Rainbow Dash thought as she began to race up, up, up.

She knew exactly what she had to do - oh, everypony she knew would be mad, but there was nothing they could do about it. Unless they could break the sound barrier. Nope - that was her, and only her, who had ever done that.

By now, the cyan pegasus had flown so high that the Ponyville stadium was but a speck on the ground. What ground? She could hardly see Canterlot, even. It was far below her and off to the side.

“One last gift I give to you, my fans, my friends, my family.” And then she was gone.

No, not gone. Rainbow was flying down, fast as only she could go. 72 years old, I’ve still got it, she thought. I’ll miss you.

“She... surely she’s not...” Cider said, as he saw the signature cone form around his mother-in-law. “She hasn’t done one in years!”

Belle nodded, agreeing with her husband. What was that mare thinking?

At his mother’s side, Dash watched his grandmother, green eyes wide.

...

The sound barrier broke. A brilliant rainbow circle exploded around the stadium, dazzling all inside - and many not. When it faded away, something was left.

Everypony around gaped at the sight before them. Many had never expected to see a sonic rainboom (or one again), much less this.

All throughout Equestria and the lands beyond, thousands of glittering rainbow raindrops hung suspended in the air. Nopony moved. It was breathtaking.

Then, after a long moment, raindrops shot towards to center of the stadium, where Rainbow Dash would undoubtedly be. Before anything else could happen, however, the spectacle continued.

The raindrops reached the center, before exploding outwards, covering the sky in a rainbow blanket. You couldn’t see the sky behind it, but didn’t really want to. Whether you bought tickets to the show or were in the farthest corners of the world, you saw a rainbow in the sky, before it disappeared.

That is, it disappeared to everycreature - with a few exceptions. Only one was in the stadium.

Princess Twilight watched as the rainbow above left to the eyes of many - not to those who were clairvoyant. She saw the shift, and followed one last trailing streak of rainbow through the air.

To her surprise, it entered a pony. Twilight leaned down to look at the infant beside her. Looking back, she saw brilliant rainbow eyes.