Fantastic Beasts and Where to Find Them Special Announcement

Tomorrow, there will be a massive Fantastic Beasts and Where to Find Them announcement, or as it was unveiled the "special announcement." So what will this announcement be?

First, this could be some sort of footage, perhaps a clip? It can't be a trailer, since they had a Comic Con trailer less than one month ago! Or an official roster of the magical creatures? Are you guys excited for this "Special announcement" for Fantastic Beasts and Where to Find Them?