Weird double header today

 I was finishing up putting away christmas decorations for the year. My wife had gone to a friends house so I  and my dog were alone in the house. The dog was curled up on a rug by the front door. I was sitting on the floor, in the parlour,gathering up miscellanous presents to carry upstairs and put away. Where I was sitting, I had a clear view from the parlour, through the diningroom and into the kitchen. As I was boxing up items the definite sound of someone coming from the kitchen and through the diningroom could be heard. I looked up, expecting my wife, the dog came bouncing out of the hall , past me, and into the diningroom where he stopped and looked bewildered. There was no one there. The dog flopped down in a very discusted manner and continued to face into the diningroom. He heard the steps the same as I and obviously also thought my wife had come in. Before I had a chance to get up off the floor a tremendous crash shook the house. We had a small section of plaster come down a few days ago and naturally I thought "Oh no, where and how much this time?" Checking over the entire house I found nothing that could have made that crash. For that I am thankful; but what was it?