I'm just guessing... Looking at that daily digest of the jokes mailing list, I gather this is what one could call a running joke. It starts in one story... and ends in another, at first sight totally unrelated story, that got posted 4 hours later. So the conclusion of the second story unexpectedly links the two stories... and I think this is what the comment alluded to: the fact that in this piece of code you suddenly get an unexpected connection to another seemingly totally unrelated piece of code. I'm still not sure what the connection may be, being unfamiliar with that part of perl's source code, but I'd be thinking in the direction of use of the same global variable in the two places, or something along the same lines.

I'm not even sure these two stories are indeed what the comment is referring to.