I understand that there is a limit on downvoting -- it doesn't cost karma, but it's only possible up to the limit of one's karma, or something like that.

I seem to recall that it is (or was last I heard) limited to 4 times current karma.

If so, a sockpuppet wouldn't have enough karma. It must have been an account with a real presence here, either bingeing on OCD or using an automated script.

The ideal outcome here may be if a PTB banned the offender, pumped Muga's karma back up then removed all traces of this conversation. This is somewhat too close to an instruction manual and primer for saboteurs.