Welcome to the dark side of 3D printing.
The hobby is best known for creating colorful toys and trinkets, but some enthusiasts are working on design files that would allow anyone to print a working gun. These don't exist yet, but some believe it's only a matter of time.
Why would a 3D-printed gun be appealing? For one, it could potentially be cheap. You can buy a preassembled 3D printer for about $500. A spool of ABS plastic to print with goes for $50. Depending on where you shop, you can buy .38 Special ammunition for 30 cents a round. The plans will undoubted be distributed free like so many MP3s.