For any English speakers in need of a translation, here's the rundown: Luffy is explaining how his Hat is his treasure, how it's gifted to him and how you shouldn't touch it. Usopp then puts it on his head and Luffy says "What're you doing?!" and wrecks him with a Gomu Gomu no Jet Bullet, then screams his name and says "What the hell are you doing?!" and then says not to touch his treasure (hat) or he'll send him flying next time. It's a Japanese meme video, it's a running joke on this channel for Luffy to say "Nani ya ittenda, omae?!" (which is the "What the hell are you doing?!" I told you about earlier), particularly to Usopp. Check the other videos out on this channel, they're just as funny, like one in Water 7 where Nami screams to Luffy about how Robin is sacrificing herself and giving herself up for the government and Luffy doesn't wanna take action because he's sleepy. And that video actually has English subtitles, so you can understand it.
