I recently purchased a bunch of fishing stuff in an estate sale. In the box was a Farallon Shark Dart that must be for use in fending off sharks. You load in a CO2 cartridge and the sharp needle like point punctures the attacker and discharges the CO2. Sounds grisly. I have found very little info on these things on the web, except that they may now be illegal to use. Are they even illegal to own?