I cataloged an odd one today - The Power of Soul by Dr. Zhi Gang Sha. On the dust jacket it says "Soul Song For Rejuvenation Download Included." I took this to mean that there's an actual download that one can retrieve - since there's another release of this book that includes a CD, I figured the download would include the same "soul songs" as the CD. It turns out I take things too literally. Apparently, this is a spiritual download that is "preprogrammed" into the book, which will be "downloaded" into one's soul, unless one is not ready to receive them. The original note in our record, which just had the text about the download as it is written on the book's dust jacket, was misleading, so I've changed it. It now reads:
"'Soul song for rejuvenation download included'--Dust jacket. This is not a literal download, but rather a spiritual download."
Still not really clear, but I'm not sure the English language is prepared to properly communicate something like this. This is quite possibly the most interesting "extra" I've ever had to figure out how to describe.