It's the highly classified Pringle-flinger: That "spool" is acutally a brand neutral housing (Pringles wouldn't pay for the advertising potential) that holds one can of any flavor or Pringles potato chips. This system is used to fire up to 10 chips per second at or near besieged terrorists. With a direct hit the sour cream and onion variety can cause instant salt filled wounds similar to papercuts. Near misses will often result in hungry terrorists abandoning their posts and cause in pursuit of the tasty spent ammo, allowing anti-terrorist troops to safely neutralize the target from a distance with conventional weapons. Of course, depending on the ethnic background of the target(s), ammo must be chosen wisely (Americans tend to respond to BBQ flavor, etc.).
Hope that clears up the mystery.