The humble Whippoorwill, a bird whose sole purpose is to annoy you as much as possible. Hunter + lowering all your stats by 1 while it's near you means you want to kill it, but it having aloof (and lowering your combat slightly) motivates you to maybe just ignore it or run from it. And that core conflict this card presents has inevitably lead to many groups being chased around the map before reluctantly taking up a round or two stabbing these birds to death. But the annoyance of this card transcends gameplay. First off, it's kind of a pain to spell it out: W H I P P O O R W I L L. Why two P's, two O's, and two L's? Why do I always seem to forget one of the P's or the O's every single time? Second, it's in the ArkhamDB twice. Here, check this page if you don't believe me: Whippoorwill. See? They couldn't even be contained in one set, let alone one campaign.
Anyway, there are certainly good tools to help deal with these now. Tony Morgan can put a bounty on them, which is hilarious and incredibly satisfying. You can get their attention with a makeshift bird call. Or you can just go full Mystic overkill and Spectral Razor or Storm of Spirits them to death. In one scenario, our Carolyn Fern chose to Dynamite Blast a room full of Whippoorwills, which is probably a triumph for the field of psychology, as it certainly relieved a lot of our anxiety that day.
Side note: Please describe to me exactly the situation in which you would ever evade one of these. Seriously, I doubt anyone has ever evaded a Whippoorwill in the history of this game. Not one person. I really want to know what situation would arise where someone would try to evade it instead of just punch it when they've presumably already purposefully engaged with it.