Meet Sonic Blast ;3
 
She’s the daughter of Soarin and Rainbow Dash (The two of them where not actually a couple. Soarin was in a relationship with Braeburn, and when they decided they wanted children, he asked RD if she could give a sample to help, since she’s a close friend of him)
 
Sonic Blast is a very sporty competitive and active pony. She enjoys flying, and racing other ponies (her family, friends, and strangers alike)  
She is kind of a speed freak, and she isn’t one to take things slow (which often leads to it biting her in the ass XD)
 
She wants to grow up to be a Wonderbolt like her father. However, despite her love for going fast, she finds staying in Appleoosa and doing slow and careful farm work to be surprisingly fun. She also has a good relationship with both Soarin and Braeburn, along with her biological mother Rainbow Dash.
 
When she flies fast enough, she’s able to generate some amount of electricity.