Malamutes are really funny about things like that. Our female will go into the bathroom and start eating toilet paper or unrolling it if we leave her home alone. I don't think it is a phase so much as just their nature to be stressed sometimes when we leave them alone. We generally take ours with us all the time in their crates in the car. Sometimes that isn't possible though and I understand that. I would just make sure you leave for only a short period of time and come right back. Make sure he has some kind of healthy chew toys - like a Kong. Maybe a treat-filled Kong would be a good idea. We put tiny bits of carrots or peas in them and let our dogs roll them around on the kitchen floor. If he associated you leaving with a treat and/or knows you are coming back 'soon' - and then extend the time gone - he may relax and not become so destructive. I think it is just that they are mad that we left them. I also try and walk mine a LOT and tire her out before I leave her, leave a light on, noise like the TV, etc.