Murray turned on me today. I am shocked. We've had him for 2 months now and he has been a great dog (came from a shelter, approx 3 year old collie mix). He has some really annoying habits like stealing the other animal's food. Today, I was constantly scolding him for eating out of Bear's and the cat's food bowls. He knows he is not supposed to. Well, I kind of got fed up, because I was trying to get my elderly cat to eat, and I made her some special food. I turned my back for a moment, and Murray was eating it. I yelled at him and swatted him lightly on the behind. He LUNGED at me, teeth bared and bit at me several times up and down my arms. It did not break the skin. He was growling and sounded quite ferocious. It really scared me. After the incident, I could tell he felt bad. My son yelled at him and made him go outside. He is still out there. What should I do? I've never had a dog of mine do this before. I know I probably scared him, but still.