My guess?
That would be a conjuration item of some sort.
Say 3-4 steps for the body, plus a step or two to summon a near mindless thing to inhabit the body. You wouldn't need to use magic control it (only enemies trigger it) and it only lasts a relatively short time. If the total was 6 steps or lower he could have had it as an enchanted item.
But I'm not the guy who wrote the magic system - I think you can contact him through Evil Hat.
Richard