You write it up and send it to the Chronicle:
Although I expected that he would be at the conference, I hoped he wouldn't attend my presentation. He did. But even in my wildest imagination I never could have foreseen that over the next three days we would share each other's company over breakfasts, dinners, and drinks. It was as if my academic karma had gone grievously awry in a previous life.
This was, after all, the scholar who had trashed (with prejudice) my book during the peer-review process and thereby scotched any chance I had with my original publisher ...