Catharti Death Grip
A technique taught in the Assassins' Guild for disabling any inconvenient people standing between the Assassin and the client, possibly terminally so in the case of the paying customer and less terminally in the case of the hired help. Apparently accomplished by pinching nerves in the neck in a certain manner. Referenced in Pyramids.
might have been devised by an emotionless Assassin called Spock, although this is pure speculation...