Half the fun in watching the recent slate of Marvel films is trying to catch the teasers and easter eggs embedded to tease future movies, and apparently most of us missed a big one dropped into Iron Man 2.
Way back in Iron Man 2, which was released before the Cosmic Cube power source was formally introduced in Thor, then prominently featured in Captain America, Tony Stark (Robert Downey Jr.) apparently flips right over some Cosmic Cube notes left behind by his father Howard Stark. The elder Stark (Dominic Cooper) was introduced to the Asgardian power source in Captain America, and apparently left behind some notebook entries for his son.
Though some keen-eyed fans had already spotted the entry, it was not officially confirmed until Marvel exec Kevin Feige told Wired how it all came about:
In Iron Man II there's a scene where Tony is flipping through his father's old notebook. I told Jon that we thought the young version of Howard Stark was going to be a character in Captain America, because we need a gadget guy, sort of a Q for SHIELD. I said, "What if the prop guy just draws a little cube on this page of this notebook? You never have to mention it, never even talk about it, it's just there." Jon said, "Sure, whatever." The trick is, the Easter eggs have to enhance the experience for those who know what they are, but not detract from the experience for those who don't.
So, be honest: Did you catch this when Iron Man 2 was released?