The Multiverseal grand prix

Rainbow Dash alone with a bunch of other heroes and villains from other worlds are transported to an interdimension race where they must race or watch their worlds destroyed

The Grandmaster and The Beyonder two interdimensional being, summon the fastest beings from versus worlds to race against each other in an grand prix to find out who is the fastest creature in universe, who ever wins will became the true speedster of the multiverse

Everyone