Belonging to MLP: Legends of Harmony
 
Great Being: But now, I want to show my appreciation in a very special way  
Her horn began to glow, while from the chests of both Comet and Flash emerged two beams of light, both crossed and floated around the dimenssion until the both combined  
Great Being: Prepare yourselves for the Greatest Miracle  
The beams combined into one orb of light, that gleamed with great intensity, them both were blinded againg and hoped to return to their world  
When the two recovered their vision, saw that they were again in the observatory, then both noticed the shining orb, as it flew through the room to finally landed softly in the floor  
Flash and Comet didn’t know what to expect from it, the only thing they knew about it was that it was a gift from the Great Being  
But when the light began to dim, both began to get excited to know what could it be, as the light faded, a silhouette became visible, both approached to it  
Then they saw it as it began to giggle, The Great Being had granted them a male foal, an alicorn foal, his coat was yellow but his wings were orange, his mane was blue but his tail was purple, the most surprising were his eyes as they were turquoise (Like the realm where he was born)  
Comet carried him with his magic and the looked to Flash, and both overjoyed by their son agreed to raise him together, no matter what hard could it be the two were determined to be his parents  
The next morning, they named him Cosmic Burst  
The notices of a new alicorn in the kingdom spreaded with a incredible speed, that Princess Luna visited them and ordered a ceremony in Canterlot to celebrate the Greatest Miracle  
At a young age, he gained his cutie mark (a star and a lightning) when decided to take both paths, Comet taught him Advanced Magic while Flash taught him Flying and began to train him as a guard, the effort he put to improve his skills granted him his cutie mark
 
I said that I would explain the origins of my own OC, if you want to see an adult version of Cosmic Burst then see “Let Me Tell You a Story”