I would so use this. A Weeping Angel face-decal for the zombie would be cool, and perhaps the decal changes when someone is looking at it, so its eyes are covered and its skin is stone-colored. Then when you look away, it changes to the scary decal and becomes zombie-colored. Death is swift. And perhaps an angel wings model for a pack on the playertype? Would it detect the admin ball in observe mode?
Sort of related: Empty Child Zombie that changes everyone it touches into a 0.7-scale zombie like it with low health, middlin' speed, a suit and a gas mask face. Then the player must turn others into Empty Children. Can heal each other, but not themselves, with an emitter like the nanogens. When converting another player into an Empty Child, the zombie plays a sound that says "Are you my mummy?"