Where's my sock?

Have you seen this sock?  A couple of weeks ago I bought three pairs of these socks on-line from Zkano Socks (http://zkano.com).  I gave one pair away (a relatively cheap birthday present, right? but nice nonetheless).  Today I laundered the other two according to instructions, that is, inside-out in warm (not hot) water and low temp dryer.  Subsequently, upon sorting the laundry, one of these socks is missing.  I made a futile search in and around the washers/dryers and carefully inspected the sheets/towels, etc., to check if the sock got caught in a random fold or in the woof and warp of some other garment.  Not to be.  How does this happen?  It happens to everybody and it is one of the unexplained phenomenonae of the modern world.  Or maybe, for all I know, ancient worlds.