In the Book of revelations there is a verse that speaks about the Mark of the Beast (traditionally 666) eventually being emblazoned on humans by Satan. Here's the verse:
"And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads: And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name." Revelation 13:16,17 (KJV)
If you Google "Revelation 13:16 UPC" or "Rev 13:116 Barcode" you will see thousands of sites that will swear that UPC codes, the bar codes that track inventory and sales for virtually every product on the planet, is the work of Satan. Those that don't credit it directly to satan see them as being tools that Satan will use and a precursor to his arrival now that UPC codes have been so widely accepted.
This isn't a new delusion. It's been going around for years. But what's amazing is how a new technology that has vastly improved inventory management and product identification, a benefit to business and consumer alike, has been given some supernatural ominous meaning by the theistically deluded.
I have to rate this as the stupidest Xtian belief ever. Have you a better one?