Reasonably enough, I took one big step back and closed the door. The hornet landed on the concrete floor of the porch and proceeeded to sting the ever living shit out of it. Then it crawled onto a dark green piece of plastic and stuing it into submission. Then it landed on the black handle of my umbrella and is still stinging it. It's been over an hour and it's still going strong. These things fly by night, too, so this could go on for a while.
I think the dog is staying outside tonight and so is the laundry. And I'm going to embrace my terror of bees, wasps, and their kin and never leave the house again, because they really are out to get me.
More seriously, I'm curious to know what has angered this bug so much. What did the back porch and some plastic do to you, little fella? ... And how soon will some bird or bat notice your distraction and eat you (and your Mom and all your sisters, if I'm lucky)? ... And what is it about human nature that gives me such a strong urge to toss something onto the porch, to see what this hornet will do?