Doomsday is set to be Marvel's biggest movie yet, with a bumper-sized cast including returning X-Men actors, the Thunderbolts (AKA the New Avengers), the Fantastic Four, and returning fan favorites like Anthony Mackie's Sam Wilson, Chris Hemsworth's Thor, and Letitia Wright's Shuri.

The teaser is simple: an incredibly low-res image paired with the hashtag #DoomsdayIsComing. That's it! But that morsel hasn't stopped fans from squinting and speculating about what it could mean. And Marvel fans seem to agree on one interpretation of the following image: It's a chalkboard.

I could spend this entire article listing all of the things we currently don’t know about Avengers: Doomsday. More than most Marvel Cinematic Universe projects, the blockbuster film has been shrouded in a unique kind of secrecy, only broken by occasional quotes from cast members and an hours-long livestream of chairs.