A reference to an unseen adventure there. No I don't expect that will ever be explored.
Despite all odds, pacing has lent itself quite well to doing a double-sized spectacular on Tuesday (the fiftieth strip, despite being numerically 49 - that's zero-based arrays for you). I was going to use the milestone to re-introduce another old familiar face but there's just too much to do between here and there.
Come Tuesday, I may be taking bets as to who this face will be.