A handful of US states levy an unauthorized substance tax on illicit drugs and alcohol.
North Carolina was the first state to succesfully add an unauthorized substances tax to its tax code. It has, to date, collected more than seventy million dollars in tax, penalties and interest from people who failed to remit taxes on things such as marijuana and moonshine.
According to state law, if you come into posession of an unauthorized substance, you have 48 hours to pay the tax, or you'll owe a substantial penalty. It's not necessary to identify yourself to the state in order to pay the tax, you simply show up at a Department of Revenue office and pay what you owe. You'll be issued a tax stamp which must be affixed to the illicit substance. Any subsequent owners of the substance in question don't need to worry about the tax as long as the tax stamp is already present.
North Carolina has issued less than a hundred of these tax stamps (known colloquially as pot stickers) in the fifteen years that they've been required. The stamp is considered unique and attractive and most have been purchased by stamp collectors.