We ran up on a nest of these babies in the Smokey Mountains during an Outward Bound course. They took off after us, without any provocation. One got me on the side of my face and then again on the hand when I slapped him off. It felt like a hot needle had been jab into me and twisted. Hurt pretty good for half an hour and swelled up, but then was as good as new within an hour.
Good thing I' not allergic to anything. Except Ovation "guitars".