As anyone who knows their DC lore will tell you, the blood-red sky on display in the latest Justice League trailer hints at big changes to come.
The comic book giant typically uses this trope to herald epic crossover events involving the Multiverse, a collection of infinite Earths inhabited by all kinds of alternative superheroes and villains.
But we don't need the crimson skyline to tell us that Justice League will be a game-changer for the DC Extended Universe, with Zack Snyder's team-up project promising to dramatically alter the status quo.
The film follows on from the events of the divisive Batman V Superman and launches in the wake of the super-successful Wonder Woman.
It finds Batman and Diana Prince attempting to recruit a super group comprised of the world's greatest heroes to combat the alien threat Jesse Eisenberg's Lex Luthor cryptically mentioned at the end of Dawn of Justice.
After the the team has assembled on screen in all of its glory, the DCEU will never be the same again, and based on how every movie so far bar Wonder Woman has been received, that might not be such a bad thing.