Quote Originally Posted by YammyMonkey View Post
That thing, while silly, doesn't fit into the illegal weapon or dangerous weapon definitions. A ballistic knife shoots the blade. A gas gun shoots a gas filled canister.

18-12-101. Definitions - peace officer affirmative defense

(a.3) "Ballistic knife" means any knife that has a blade which is forcefully projected from the handle by means of a spring-loaded device or explosive charge.

(d) "Gas gun" means a device designed for projecting gas-filled projectiles which release their contents after having been projected from the device and includes projectiles designed for use in such a device.
If it's the only thing on hand to defend yourself with use it. A cast iron skillet fits the dangerous Weapon Category. In some states & countries, more than others.