Is it known if the dog was adopted? I've heard sometimes adopted dogs could be triggered randomly and act out for w/e previous ptsd they may have gone through with previous owners. Abuse, negligence etc... Buddy of mine adopted some mutt, at his kids bday party the dog attacked his mom by biting her in the arm but let go. Like a reflex bite, nothing too bad. Kids hit the pinata then it partially broke, kids ran in then the mom walked up to overturn the pinata to let out all the candy. Dog shot up out of nowhere and bit her in the arm. Fastest reaction I've seen to a few of us 250 pound guys ran up to help out. The dog only bit her once but got her good, it let go of her before we could get to them. Never seen anything like that, dog ran off to a corner of the fence with the tail between its legs like it knew it fucked up.