Wednesday night’s conclusion to a two-part CW television event, as improbable as it sounds, has major ramifications for DC Comics as we know them. The Flash/Arrow crossover, heavily hyped for weeks and christened #Flarrow on Twitter, swept through superhero tropes like lightning (sorry) and cut them down with an arrow in the eye (okay, that one was unnecessary). As good as it was—and believe me, some parts of it were downright magical—there were significant missteps as well, which could easily be repeated in DC’s upcoming Batman vs Superman: Dawn of Justice if Warner doesn’t learn from this experience while it’s fresh. Spoilers follow.