What is "harm"? And what's the point of "harming"? The most common one are "physical pain" and "to inflict pain physically", respectively. But when I said "harm" it is most certainly mean "an action that could and might harm those". It would mean that anything that would deliberately ail something count as harming that something. For example, casting a petrify count as harming even if it does not inflict physical injury, as it is an act that would harm the affected unit in the sense that it will be very vulnerable. So to answer your question, nothing bad will happen to this unit as this unit cannot be harmed in any way possible.