This is a blowgun I made out of an old pen and an Altoids Smalls tin. I cut holes in both sides of the tin, cut down the pen to the right size (and also removed the components from the pen, making it a hollow tube,) and then I taped in the pen, leaving a small bit for a mouthpiece. The ammunition (bb pellets) fit neatly inside. You can also put in some actual Altoids or other mints, to make it less suspicious. It is a great blowgun to use as a backup, or to keep in your pocket and snipe your friends at school. I actually added some Velcro to mine, so it sticks to my main blowgun (the "3 foot metal blowgun" that I show in another instructable.) Be safe and have fun.