@AvengingFemme Oh yeah! Someone could do a PSA with folks dressed as the Ghostbusters telling people to "build your ghost gun now" before armed bigots try to turn you into a ghost yourself.

Note that 3d printed lower receivers (the only serialized part) have become rather common, so no law against "ghost guns" can keep you from owning an AR anymore.

The upper receiver has to handle the forces of cycling the bolt so successful prints of this are rare. They are possible because the locking lugs that hold the bolt closed are in the steel barrel extension, not the soft aluminum upper receiver on a normal AR. The upper receiver though does not carry the serial number, is not registered or traced, and is as legal to sell for cash as a barrel or a stock.