At Comic-Con, Marvel Studios revealed a prop of a giant hand. This is the gauntlet of Iron Man's huge Hulkbuster armor in Avengers: Age of Ultron and, as you can imagine, this suit will face-off against the Hulk at some point in the sequel.
More detailed photos of the Hulkbuster hand have emerged and you can see those below.
And for a size and scale comparison look at this screenshot from Marvel's live stream during Comic-Con...
Avengers: Age of Ultron is currently filming in the U.K. and is set to release in theaters on May 1, 2015.