Well, folks, the mystery has been solved. Nova and LaLa both correctly guessed that the Mystery sock is the Cabled Sweat Sock from the Spin-Off book Socks. This is an unfortunate name for such a lovely sock. Sweat Sock. Indeed.
Both Nova and LaLa employed cunning investigative skills to solve the mystery and both have won fibery prizes.
The Socks book is one of the oldest books in my knitting library. I made some of my first socks from it. When I was searching for the perfect pattern to use with my Wollmeise I remembered this pattern and was only too happy to pull out the book again. One of my goals for this year was to knit a pattern from every sock book I own. I have a terrible tendency to buy pattern books and then never use them. I'm doing well toward meeting my goal though I still haven't used either of the Sensational Knitted Socks books (though I did recently try, remember?). I'll have to tally up the patterns and books I've used before my blogiversary.
Congratulations Nova and Lala! Good detective work.