There isnt just one example of invisibility.
Since that indeed is impossible, making every body part magically have 0 resistance against light and let it pass through. Na-uh.
But what if you had a "slippery cloak" that would be 'slippery' in terms of the fabric/material put on the outside of the cloak, and light slides around it and keeps going somewhere in the general angle of how it came in (i.e. there would be a slight distortion in the air, from certain angles, possibly)
However even if the material was completely 'clear' otherwise, like from the inside, if light doesnt get from outside to your eyes you cant see... so maybe cut holes for your eyes? but this of course defeats the purpose, eh. But i dont think they would notice a small eye-hole, would they? lol