Sonic Rainboom!!! Everyone's favorite pony on My Little Pony: Friendship is Magic is Rainbow Dash and now you can show everyone how much you love Rainbow Dash and her special power--the Sonic Rainboom--now when you wear this My Little Pony Sonic Rain Boom Juniors Turquoise Blue t-shirt. Rainbow is the fastest pony in Equestria and if you wear this officially licensed, blue Rainbow Dash tee you'll be 20% Cooler.