Whispers of the Old Gods looks like Blizzard's new Hearthstone expansion

Details on the next expansion for Hearthstone: Heroes of Warcraft appear to be leaking, sometimes in the strangest ways. And it appears that expansion will be called Whispers of the Old Gods, and focus on the heavily tentacled, evil eldritch gods of the Warcraft universe.

Oddly enough, one of the bigger leaks that seems to confirms Whispers of the Old Gods is a painted billboard that's currently going up in Brookyln, New York. A member of the Hearthstone subreddit spotted and photographed the in-progress ad on the side of a Williamsburg building.

We checked out the mural for ourselves earlier today and it appears to be still very much a work-in-progress (and the painters have finally covered up the logo of the supposed expansion).

One thing we know for sure is that Blizzard has some sort of Hearthstone announcement planned for tomorrow, March 11.

Join us March 11 as we announce what's next for #Hearthstone! https://t.co/4JLz4xIPCY pic.twitter.com/NHhenPTO1T

— Hearthstone (@PlayHearthstone) March 4, 2016

So what is Whispers of the Old Gods? YouTuber "Disguised Toast" has an excellent rundown on what it's probably all about: giant evil tentacle monsters. He provides some compelling evidence, thanks to some hints dropped by Blizzard itself.

For a look at the future of Hearthstone, read Polygon's story on how Blizzard plans to keep its collectible card game fresh and balanced in the coming years.