Did you happen to see a rubbery, agape, slightly-disproportionate Walter White wandering around Comic Con? Well, turns out that was a matryoshka doll of Heisenberg, at the center hiding Cranston himself. This fact was revealed at AMC's Breaking Bad panel, when Bryan Cranston arrived and removed his mask, started kissing it, then helped co-star Aaron Paul kiss it in a three-way make-out session that had even creator Vince Gilligan taking photos.
Here are some more that other people took. Hopefully they don't spoil the sexy series finale.