Bungie has posted on its twitter channel image showing a mysterious Master Chief's helmet, indicating that this week will "something big" for Halo fans. Since the developer is busy with Halo: Reach, it may mean an image like that? Perhaps an indication that Master Chief will appear in the game somehow? Surely the fact that the news comes on the eve of the first April is at least suspected: that there are simply preparing an April Fool? Find the image below.