One Sunday afternoon I was walking the Swannanoa River path near Warren Wilson College. Walking in I had no problems, but coming back down the path I was stopped by two guys and a little girl warning me to stop where I was because there were a bunch of bees near me. I took a few steps back and looked up into the trees and I saw a huge nest with some kind of large, angry swarm around it.
Not sure how I passed them unscathed while strolling leisurely in. Maybe something made them angry while I was up the trail. In any case, I had to sprint past them to get out and they still chased us all the way down the trail. I ended up with six or seven good-sized welts. They were so incredibly aggressive, and the nest was so strange looking, it made me wonder what they were. If anyone out there saw the nest and knows what kind of insect they are, I would be most grateful to have my curiosity satisfied.
— Jarrett Leone
Asheville
My guess is someone threw a rock at the nest shortly before you got there. Probably a big, gray paper nest?