The fully-funded Automatic Rubber Band Blaster Kit will sell you a AK-3DP that fires much-less-lethal rounds: rubber bands, which can be fitted to snap-in cartridges for no-time reloads. $5 gets you the STL files so you can print your own (you'll need to add the motor, etc yourself); $19 gets you a kit. Creator David Dorhout lists some relevant experience in his bio, but not much actual manufacturing (which, given that this is a kit, will be much simpler than selling completed items). Caveat emptor, as with all Kickstarters.
Squeeze the trigger briefly and fire once, hold it down and release a torrent of rubber bands like never before seen. Quickly reload by simply replacing the barrel and keep going. Truly, the RBB-32 is the boss of rubber band blasters… You've had that 3D printer sitting on your desk printing out all kinds of respectable things like gears, enclosures, and other serious parts. However, you've always wondered if there wasn't something more that it could do, something that would really stand out and possibly get you that reprimand at work you've always wanted.
Automatic Rubber Band Blaster Kit!
(Thanks, David!)