A spell in a folksong that lets faeries join a harvest revel, in disguise, but not harm any of the drunken mortals on their way home. Also, a note on a new game, Magonomia, Kickstarted by some of the Ars Magica writing crew. See https://www.kickstarter.com/projects/shewstonepublishing/magonomia-the-rpg-of-renaissance-wizardry