@Crubleigh He could have been walking home and got into a fight; you teleported him, interrupting the fight, but he was still in "fight mode" and wandered off to go find his target. The battle with the saber cat "reset" his AI.

Already I have re-encountered (and now slain) the offensive little worm now. So that just confirms what the source code already proved!

Source code: The ultimate in canonical sources! Thanks, now I just have to hope he spawns again some time soon -- I really don't want to let those comments about my mother stand!! :P