The Russo Brothers are at it again. To announce that their work on Avengers 4 has wrapped, they posted a cryptic image to Twitter, prompting Marvel fans to start theorizing on what it all means!

With Chris Evans finishing his own duties as Steve Rogers, a.k.a. Captain America, in recent weeks on Avengers 4, it was only a matter of time before filming on the next Avengers movie came to a close.

Of course, as the Russos always do, they couldn’t resist whipping the Marvel fandom into a frenzy. Their latest picture, accompanied with the hashtag #wrapped, is as cryptic as they come. It features a bright blue, glowing object, which is difficult to decipher. Though that hasn’t stopped Marvel fans from trying.

The prevalent theory is that the image could have something to do with Adam Warlock. Adam Warlock was first introduced as a potential character in Guardians of the Galaxy, Vol. 2. Following the battle on Ego’s planet, Ayesha — whom the Guardians had stolen Anulax Batteries from — decided to take her revenge by creating a being capable of destroying the Guardians. Ayesha named that being Adam.

In the comics, Adam Warlock has long been a member of the Guardians, as well as an enemy of both Thanos and of the Magus, a future evil version of himself.

James Gunn had previously confirmed that Adam “will be a part of the future Marvel cosmic universe and a pretty important part of that.” With Guardians 3 shelved for now, his introduction could very well have been moved up to Avengers 4.

Whatever the image means, fans will have plenty of time to speculate on it. Avengers 4 will premiere May 3, 2019.