Ummon was a Zen master in ancient China. https://terebess.hu/zen/yunmen.html Once a student came to him and asked, “What is the highest, most profound teaching of all the buddhas and the patriarchs?” Yunmen replied, “An appropriate response.”
In his gripping short story Werewolves in Their Youth, Michael Chabon
recalls his personal experience facing a bona-fide werewolf in a very real moment in both their lives, and saying just the right words to break the spell. The author tells the story here: https://www.thisamericanlife.org/188/kid-logic-2001/act-three-8
where you may see for yourself if this is the kind of response Ummon is referring to.