At a countryside house of a friend, central Brazil, we spotted this inside the house. It was pretty big, around 10cm long. As I can only post one of the pictures, I chose the best one. I hope anyone could identify it for me.
Thank you all. I've heard about the "armadeira" and it's a common spider here in Brazil, by looking at the other pictures I took and comparing them to images I found online, it looks to be the phoneutria nigriventer. It was indoors and we left it there. If I knew it was a little dangerous. I'd have taken it into the woods. Next time someones there we'll have to be careful.
The Brazilian wandering spiders appear in Guinness World Records 2007 as the world's most venomous spiders, and are considered to be responsible for the most human deaths due to envenomation from spider bites.