Some events are just universal: everyone sharing the same experience at (about) the same time. And one of those events is that when Loki meets Hulk in The Avengers, the audience busts out laughing and drowns out the dialogue briefly. This is what Hulk said in that scene.
Something else you couldn't hear? The sound of a deflating balloon. But it's there, hidden even more than Hulk's line.
Loki is the 6" version released at Walmart last year, while Hulk is the Marvel Select movie Hulk, which hit stores on the same day this toon went up. And that really is their comparitive size, we didn't make Hulk look any bigger than he actually is.
Caption: Judging by the numbers, we know the odds are good that you went to see The Avengers last weekend. And we know that when Loki met the Hulk, you couldn't hear what was said because the laughter was so loud. So here, as a public service, is what you missed:
Hulk: Puny god.