Legend and comic books tell us that it is a precise and forceful strike, with delayed yet fatal result, sometimes taking days or weeks to do its work.
It is subtle, quick, almost unseen and usually delivered by a monk or some warrior priest with a topknot. Uma Thurman used it to great effect in "Kill Bill: Vol 2." When she was done, she flashed a smirk of wistful sadness.
That's what happened to Donald Trump's presidential campaign, which received the Touch of Death from Megyn Kelly, the warrior priestess of Fox News.
Kelly didn't flash the smirk of sadness. She doesn't wear a topknot. But at the Republican presidential debate in Cleveland last week, she asked questions Trump didn't like. So angry was he that he began raging in public, and over the weekend, he did what had been considered impossible, even for him.
Trump gutted himself with his own vulgarity.
And he was immediately banned from the conservative RedState Gathering in Atlanta for his boorish comments about Kelly.
If it hasn't happened already, it will happen soon: profound realization blossoming in Trump's blue eyes. And thinking back, he must see Kelly in black on the set in Cleveland, how she touched him — eyes sparkling, defiant — with that line about how Trump wanted to see a woman on her knees.
Many Republicans missed it, perhaps blinded by legitimate disgust of their milquetoast party leaders, a disgust that Trump knows how to feed. And many liberal Democratic analysts missed it too, thinking Trump did passably well. Perhaps they were too busy thinking of issuing snarky tweets.