Arrowverse: Every Major Easter Egg, Clue & Reference To 'Crisis On Infinite Earths'

Newspaper headline or not, you can't have a Crisis without multiple earths and, well, that's exactly what we got in The Flash's second season. Zoom's introduction brought with it the introduction of Earth-2 and once that can of worms was opened, there was no turning back.

Within a few episodes, we had Team Flash discussing the multiverse theory, and the possibilities of what all these multiple Earths could look like. Using Professor Stein, the writers helped break down what this meant for the show and, in extension, the entire Arrowverse. They even had Stein use the term "infinity" when he discussed how many earths there were.

On the surface, it was a neat little reference to an iconic comic book. But in reality, it may have been a subtle warning of things to come.

With the multiverse officially a part of the Arrowverse, it made the possibility of a Crisis a little more likely.