Season four brings a new threat, and because we do nothing but provide you with truly useful information, we can tell you that the cast has ruled out aliens, hamsters, robots and Godzilla. Whoops. Did we forget to say Spoiler Alert?! "No one is ever going to guess," Norman Reedus (Daryl) tells us. "It's really clever." We can tell you, this new threat is the hardest one yet to contain. Also, you've probably been in contact with it already. Runnnnn, runnn for your life!!!