THE FLASH – New Trailer (2023) Ben Affleck, Michael Keaton, Ezra Miller Movie

Warner Bros
The inspiration behind this video:

While the new trailer for The Flash debuts the DCU's brand-new Supergirl, her origins may be taking inspiration from another major comic story beyond Flashpoint. Played by Sasha Calle, this new version of Superman's cousin will come onto the scene during a collision of worlds thanks to the unintentional efforts of Barry Allen's Flash. However, some interesting teases suggest Supergirl's debut will resemble one of DC's greatest Elseworlds stories from the comics.

The clashing of timelines seen in The Flash trailer is all inspired by DC's Flashpoint by Geoff Johns and Andy Kubert. In the comic, Barry Allen wakes up to a massively altered reality, one in which he has no powers, and the lives of the Justice League have been massively changed. This all stems from his decision to go back in time and save his mother from being murdered, a moment that created a massive domino effect. As such, this is the basic framework The Flash will be working with, though it looks like Supergirl's origin will also adapt elements of a classic Superman story from Mark Millar.