Ninja Pen with Sound Effects
It's the classic ninja pen: a knife that goes "SHHHING!" when the tip is clicked, and the ninja ballpoint extends, ready for you to write ever-so-deadly letters.
Carry one in your pocket for quiet attacks. Wip it out and attack that piece of paper! Remember, you are Ninja and you have every tool in your arsenal for silent but deadly attacks, and we're not talking about the deadly farts you've been letting rip.
Ninjitsu is an ancient and secret art and we have stumbled upon the ability to make these near magical weapon-tools. Legend has it that the ink is infused with the blood of the enemies of the Ninja.