Hulk versus Loki was a funny clip in the movie The Avengers, but Loki is a god, isn't he? How can the Hulk be so much stronger than him?
Loki isn't a god. Odin says this explicitly in Thor: The Dark World:
Odin: We are not Gods. We are born, we live, we die, just as humans do.
Loki: Give or take five thousand years.
However, a more intuitive answer to the question would be: sure, but Hulk is also a god.
The Asgardians are the source of Norse mythology on Earth; this is referenced a few times in Thor, but a particularly interesting example is when Fandral is trying to talk Thor out of invading Jotunheim:
Fandral: This isn't like a journey to Earth, where you summon a little lightning and thunder and the mortals worship you as a god. This is Jotunheim.
This line suggests that Thor and his, for lack of a better word, entourage have visited Earth in the past, and there inspired the Norse myths about Thor and Loki. So in that sense Loki is the God of Mischief: he's the inspiration for the mythological figure.
It's understandable why primitive humans would have regarded Loki (and certainly Thor, with his lightning rod hammer) as a god:
- He has strength, stamina, and reflexes beyond that of even the strongest human
- He can create illusory versions of himself that appear to act independently of the real Loki
- He appears in a column of rainbow-coloured light that comes down out of the sky (or he would have to early humans)
The first of these advantages is biological. The other two are technological, and he has to use them consciously. But he's not indestructible; he can be hurt by a sufficiently powerful force (Thor gets pretty banged up by the Destroyer in Thor), and he can be killed (as has been covered on this site before).
Now let's look at the Hulk:
- Stronger than a normal man
- Practically invulnerable. He can be hurt, but it takes someone like Thor or Iron Man to do it; he shrugs off bullets like they're mosquito bites, and even getting brained by Thor's hammer just makes him madder
- Surprisingly quick for such a big guy
Drop the Hulk into 10th century Norway, and I guarantee you he'd be taken as a god.
But all of this is building up to the answer to the question: how could Hulk overpower Loki.
- Hulk is physically stronger than Loki. Loki isn't all-powerful, he just thinks he is. Gamma-irradiated muscles beat out Frost Giant physiology
- Loki wasn't expecting an attack. Loki isn't omnipotent at the best of the times, although he's generally clever enough to look it. But this isn't the "best of times"; Loki is in the middle of a minor breakdown, and is clearly not operating at peak efficiency.
So the Hulk takes advantage of a moment where Loki isn't fully capable of deploying his tricks and misdirections, and beats him with sheer brute force.
And Tony's floor.