To the right species of bee, this looks like another very aggressive bee, and it goes and bonks it on the head lots and lots of times to try and drive it away, and, of course, covers itself with pollen.

So we decided to see if flies could be provoked into showing the kind of behavior that you see by the proverbial wasp at the picnic table, you know, the one that keeps coming back to your hamburger the more vigorously you try to swat it away, and it seems to keep getting irritated.