That's him, Ultron, the robot villain of The Avengers: Age of Ultron. And he looks, more or less, like the comic book version of the character. His mouth isn't quite as Ultron-y as you might hope, but otherwise this is pretty identifiable as Ultron, the robot who has battled the Avengers again and again.
In the comics Hank Pym creates Ultron, but since Hank won't show up in the Marvel Cinematic Universe until after The Avengers: Age of Ultron the duty falls upon Tony Stark. And to make Ultron a serious threat to the entire team (so that they don't have to stand in line to hit him like the henchmen in a martial arts movie) the villain creates an army of Ultrons, who you can see hanging around in the background, complete with a weird Styx joke (this is like the new thing at EW, adding jokes to their covers).
I'm pretty psyched by this reveal. What do you guys think?