Certainly been a Houla Monster invasion on the forum lately!
He looks catahoula to me. OMG...turn him brindle, and it could be Voodoo! Even down to the ear set! See?
Catahoulas are traditionally drivey dogs, although it can vary based on breeding. They're smart, stubborn, tend to be dominant, physically capable, slow-maturing and intensely loyal to their families. They are happy and fun dogs with their people, but do tend to have protective instincts, especially about their territory, and can be aloof with strangers. If you search the breed forum, there was a pretty detailed thread about them recently.