Let the speculation begin. Bungie has filed a trademark for something called "Matter."
No big details have been leaked or revealed about Matter but the keen eyes over at Eurogamer noticed that the trademark has been filed under two categories: "computer game software" and "online entertainment services." The chances here are pretty good that whatever Matter is, it's game-related.
Also, here's a logo that's possibly work-in-progress placeholder art filed with the trademark:
For more on Bungie, check out our review of Destiny 2: Forsaken.