Nobody really knows what it is, or why it's announcing that. As I mentioned, even a few Blizzard employees have no idea what it is, though they're looking into it. The only 'ice stone' that crops up when Googling or Wowwiki'ing around to find this thing is the objects from the Midsummer Festival that we interacted with last year. It's possible that the team responsible for world events was working on an update to the Midsummer Fire Festival and crossed some wires somewhere. After all, if any of the holidays need an urgent update, it would be that one.