Okay, suppose I have a ten-foot-pole and some means of causing it to become ethereal while still controlling it (such as only part of it turning ethereal, myself turning ethereal with it, etc.). Now, I shove part of this pole through the space that is, in the material plane, occupied by someone's head. Now I make the pole material again. Given that there is a pole trying to occupy the same space as his head, does the subject of my experiment die? Is there an official answer to this question? Is there a logical answer that can be derived from a greater knowledge of game mechanics than that which I possess?