Ed Boon, the head of Mortal Kombat and Injustice studio NetherRealm, enjoys teasing things on Twitter. He’s done that again today, posting a message that might suggest a beta for Injustice 2 is on the way.

He tweeted the image below with the caption, “Don’t know why, but I can’t help feeling like there is something missing today….” The image shows off a series of Greek alphabet characters but leaves out “beta.” This could be a reference to a beta for the fighting game.

It’s been a big week for Injustice 2. Publisher Warner Bros. released an awesome-looking story trailer and confirmed that Darkseid is joining the roster, but the only way to get him is to preorder right away, apparently. Additionally, information about the game’s various premium editions was revealed.

Some of the playable characters in Injustice 2 include Harley Quinn, Deadshot, Batman, Superman, Supergirl, Aquaman, Atrocitus, Gorilla Grodd, Blue Beetle, and Wonder Woman.

Injustice 2 launches on May 16 for PlayStation 4 and Xbox One.