Great Caesar’s ghost, did that just happen? Welcome to “Watch the Arrowverse,” the weekly show where we take a look at some of the Easter eggs, important moments, and theories from all of CW’s superhero shows. On this episode, we’ll be looking at the season premieres of “Supergirl”, “The Flash”, “Legends of Tomorrow” and “Arrow.” As we’ll be discussing the heroic details from all of those shows, we’re putting up the spoiler signal.