[This is a part of our Grim Meathook Future][link]. The knife’s handle houses a small cartridge of compressed gas which, when activated, exits from a small shaft in the blade.
[link]: http://www.dailymail.co.uk/news/article-1035729/Britain-alert-deadly-new-knife-exploding-tip-freezes-victims-organs.html “Britain on alert for deadly new knife with exploding tip that freezes victims’ organs | Mail Online”