The Brazilian Mastiff, also known as the Fila Brasileiro, is a large working breed that hails from Brazil.
It has extraordinary tracking abilities making it a great hunter.
But, this guy's unpredictable temperament and aggressive tendencies have put it on the dangerous dog list.
What's interesting though, is that the first year of a Brazilian Mastiff's life can make a huge difference, like that of many dogs.
If the puppy gets plenty of positive socialization with people and other dogs early on, the chances of it being aggressive when it grows up decrease significantly.
They're extremely loyal too, which is a bit of a double-edged sword since it will attack people if it means protecting its owner and family.
Lack of socialization, on the other hand, can have serious consequences. And that's why the Brazilian Mastiff has been officially banned in countries like Denmark, Israel, the United Kingdom, and Norway, among others.