Just in the past week or so Diesel has started to get more violent, for lack of a better word. He is growling and barking a lot more. but it is not a normal growl like he used to do when we played, its a mean growl.. and this morning when i get ready he usually sits out side my bathroom door and chews on his toys but instead out of no where he came in and bit my foot. I had not done anything different or moved quickly or anything he just bit me. At first it only happened every once in a while but now it happens alot. does anyone have any advice on how to stop him???