system
Given the following post, respond as if you're commenting on Reddit:
human
How did Bruce Banner suddenly get control of the Hulk in the Avengers?

On the aircraft carrier thing, he had 0 control and just smashed everything to shit. Then the next time we see him, he's in complete control. How did that happen?
gpt
At the end of The Incredible Hulk it's strongly implied that he is able to change whenever he wants.

There are basically two Hulks. The one we saw when Loki's manipulation caused Banner to lose control and the one Banner deliberately became during the fight with the Chitauri.

The first Hulk is based on pure, uncontrollable rage. The second has Banner in the back of his head, making sure his anger is directed at the right people.