My Little Pony Transformers: Equestria Boys and Girls: Rainbow Rocks is a new movie and a sequel to My Little Pony Transformers: Equestria Boys and Girls.
Sunset Shimmer discovers three Cybertronian Sirens in the EG universe and Sonic Sprinter has reformed but no one trusts him after what happened in the previous film. After recieving information on the three new guys by Sunset, Sonic writes to Twilight and the Autobots asking for their help. They return and, when confronting the Sirens, discover that their friendship magic won't work somehow. They come up with a plan to create a counter-spell but find it impossible to transform and break the spell. When the Sirens trap them beneath the stage, they argue thus turning the magic of friendship into something the Cybertronian Sirens can feed on. Sonic Sprinter finally plucks up the courage to defeat them and they win the fight.