Video at link. Call that the death touch. I've never seen anyone become incapacitated just over pain before.
https://www.funker530.com/green-beret-beats-peruvian-special-forces-officer-with-one-finger/Green Beret Beats Peruvian Special Forces Officer With One Finger
As soon as the match begins, the fighters close in. They attempt to strike at the same time, and the Green Beret buries a lightning quick finger jab into the Peruvian officer's eye socket. The pain inflicted on the Peruvian continues to build, and in a few seconds he falls to the ground, incapacitated.
The Green Beret was using a form of Chinese martial arts known as Kung Foo San Soo, which is a system of techniques designed to subdue an opponent and end the fight as quickly as possible. Top targets include testicles, knees, kidneys, and obviously the eyes, as demonstrated in the video. Due to the brutal nature of the technique, there are no official sporting associations or tournaments designed around San Soo.