If any story ever seemed to exemplify the dangers of trying to be too clever when teasing your fans, it could be this one. Because unless this is all an elaborate red herring (and to be honest, there's a decent chance it might be), then Halo 4 developer 343 Industries might just have accidentally leaked a fairly significant page of the game's script all over the internet.
Originating in a post on NeoGAF (potential spoilers through that link obviously), the story goes that a raft of information regarding a (or potentially the) climactic battle with Halo 4's previously unconfirmed antagonist is visible during one brief shot in 343's recent "A Hero Awakens" documentary video. A re-watch and some judicious pausing reveals that the information is indeed present, via what appears very much to be a page from the game's mocap performance script.
Turning up at around the 3:55 mark, the page is only in focus on screen for the merest blip of time, but that didn't stop GAF user Slightly Live from digging out possible details of the identity of the game's primary enemy, some new abilities for Cortana, and a real sense of the new enemy's level of power. None of those details are going to be fleshed out on these pages for the sake of avoiding inflicting accidental spoilers, but interested parties can find them all on the original NeoGAF post, along with some more speculation driven by a currently unreleased (but heavily previewable on Amazon) Halo novel.