User blog comment:Johnnybravo44/THOR!!! (oh yeah, and FCBD!)/@comment-1713281-20110507041141/@comment-3359393-20110507120535

I think the item in the box was the cosmic cube. I don't know any plot to the upcoming Captain America aside from: Nazis are bad, the US is trying to stop them, they make Steve Rogers into Captain America. My theory is the Red Skull is attempting to make the cosmic cube, which he may or may not succeed in during the movie. The cosmic cube is obtained by S.H.I.E.L.D. and they posess it until current times when it was shown that Loki now wants it, which would be a goal of his in the upcoming Avengers movie. It appears to me that the showing of the cube is a nod to both the Captain America and the Avengers movies. Just a thought, but i think it may be pretty solid.