Drawn by Tsitra360 as a commission. https://www.deviantart.com/tsitra360  
This one was special to me as someone who grew up watching the original 1980s My Little Pony series, now referred to as Generation 1. G1 fans will recognize G1 Tirac and Danny Williams the human riding Firefly the Pegasus who was the original Rainbow Dash that Lauren Faust wanted to use before being told she couldn’t due to copyright problems.
 
This piece is a reference to the very first MLP media that ever existed, Rescue At Midnight Castle from 1984. In it Tirac here is kidnapping ponies to transform them into steads to his chariot so he can fly into the air and open his bag which contains the Rainbow of Darkness. Meanwhile Firefly realizes the Ponies need help and goes to the human world to get Megan Williams (I used her brother Danny here for variety sake :P) Together they get the Rainbow of Light Locket and then go to the castle to rescue the Ponies, Long story short. Tirac opens his bag and the Rainbow of Darkness comes out and then Megan opens the locket and the Rainbow of Light comes out. And then they sort of combine for a bit before light overtakes darkness. And then Tirac sort of explodes and dies lol Kind of anti-climatic.  
And that’s where this com comes in. I wanted to epicify that fight by making it more a beam struggle, and make the characters directly involved with the beams, and finally making the whole planet at stake by making them planet sized. Anyways I hope you enjoy this piece my fellow G1 fans!