Anchorhead said:
I assume it's that and not that actual magic box he never opened. Still seems a bit of a stretch to put it in the cartoon. The Bad Robot shirt works better.
No, the mystery box is his whole shtick. It's his belief that mystery itself is what's important. So he's made it a habit in most of his productions to introduce mysterious elements in them and then never resolving them. Most of the time because there never really was an answer. They're mysteries for mystery's sake and I've always found that incredibly lame.