This one apparently is a hit-and-run type.The thing you have been missing is that it is the same guy (or guys, if there happen to be a few sharing the same resources), day after day.
Do we occasionally get different trolls? Yes. But about 90% of the newbie trolls trace back to the same two ISPs.
Ah. That makes sense. Thanks. Now I won't whine as much when they/he get/s the insta-ZOT! ;^)