There's still a lot of confusion about the details of the monster(s) in Cloverfield/1-18-08. First there were some smaller monsters, then there weren't.
Now Dark Horizons has some details about the movie that were apparently confirmed by "two agency sources." Can it even be called a spoiler? I'm going to take all this information with a grain of salt. And until there is absolute proof, I'm probably not going to report on this topic again. There's just too much speculation, and even after we have a dozen "agency sources," the details are still not fully understood.