Knife with a CO2 cartridge will put you in a world of hurt

DVICE: Knife with a CO2 cartridge will put you in a world of hurt:

"Here's a little piece of advice for you if you're ever attacked by a shark: sharks absolutely hate it when you stab them with a knife that also shoots compressed air into them. It's just excruciatingly painful, see? All you need is, you know, a knife that has a CO2 container in the handle that's designed for blasting air into gaping wounds."