According to the description of the countdown video, the co-op zombie shooter "Back 4 Blood" is being advertised as "coming to Xbox Series X|S, Xbox One, and Windows 10 PC at the launch of Xbox Game Pass." The video has since been made private, but a screenshot of the description was captured and shared by a reddit user.

Back 4 Blood has an event scheduled for this Sunday under Warner Bros. right after Microsoft's own conference, and this news could have been scheduled to be announced at either. This would not be the first game news that was accidentally leaked just before this E3 event. Many game announcements have been leaked, some of which have already been confirmed, such as "Two Point Campus."

The original Left 4 Dead game is still beloved despite its age. So much so that a community map was officially added to Left 4 Dead 2 last September, giving the 2009 game its first major update in seven years. The spiritual successor to the series is being created by the original creators, Turtle Rock, and revamps the series with additions such as a deck-building element that adds a different kind of strategic thinking to the undead-cleaving gameplay, and next-generation enhancements that make the equivalent of a tank really big In either case, the modder will be able to use the tanks to take out the enemy's enemies. Until, of course, the mods trade the tanks for "Thomas the Tank Engine."

Back 4 Blood was recently delayed, but the open beta will be playable this summer, with a full release on Steam and possibly Game Pass on October 12. For more information, this weekend's Warner Bros. presentation will only talk about Back 4 Blood tomorrow at 2 p.m. PT/10 p.m. BST.

- What's Next' Full E3 2021 schedule here - Full list of all games at E3 so far here