In the overworld, enemies disappear and I get mora and exp but no drops. In dungeons, nothing happens. Except in some, where they take a very small amount of damage/their shields take a very small amount of damage every second or so, IIRC. Against overworld bosses, the bosses will disappear and then reappear after a few seconds.
I don't think attack teleporting has ever done anything for me, but I'll test it out again.