I was walking to a deer stand in Texas once and came upon an armadillo rooting around in the leaves. The ground and leaves were damp from rain, so I wasn't making any noise as I snuck up on him. They have good ears and good noses, but their eyesight is poor. Since I was going hunting, I didn't plan to shoot him (too much noise on a peaceful calm day), so I got right behind him and goosed him with the end of the rifle barrel. That dillo jumped about a foot in the air and came down looking all around. He saw my leg, but to him that was just a tree trunk. After he puzzled on whatever it might have been that goosed him, he went back to rooting in the leaves. I goosed him again and he jumped at least a foot in the air. When he landed he really had a strange look on his face, like maybe the area was haunted. He was quite disturbed by being goosed, so he slowly crept off, looking back often. He never made a sound during the whole episode. I know that I'd have at least squeaked if I was goosed by an invisible hand.