I guess I have to give this info out since you calling me on it but enemy caster was completely mauled by a similar creature at one point in full public view and no one saw his actual attacker he was just kind of mauled to death by some completely invisible enemy not even he saw coming. Those are not the same exact enemies merely copies made by Greys but he has imbued a similar attribute into these creatures. This isn't some round of the bout magecraft he's using its extremely potent actual magic.