I'm going to preface this by saying that the following was an honest mistake by my neighbour and has been taken care, but for next time, what should I do?
Yesterday I walked out of my house to get the mail and, halfway down the steps, the huge untrained dog from next door ran out the garage and stood at the bottom barking at me like mad. If I backed up a little, he advanced. He had his tail tucked under his legs and wouldn't let me move. I stood there, petrified, for a few minutes then slowly (very slowly) made it back toward the door. When I was a couple of steps from it, the dog ran halfway up the stairs. I panicked at this point and jumped inside. He kept on barking for a little while, then stopped and went back to the garage.
I'm sure this won't happen again with this dog -- the people next door feel terrible and he had jumped out of his pen when no one was home. But what should I have done wrt the dog? What's the best way to handle a dog like that.
I'm somewhat scared of big dogs and this was terrifying.