As for making the surface of water disappear--that is a known hazard of polarization.  I knew a guy who almost killed himself landing an airplane on a lake--turns out he was breaking in a new pair of polarized flying glasses and the word had not yet spread about some of polarization's drawbacks.  With the lens filter, of course, you just rotate the front glass 90° and you are back to the "real" world.

"Remember the I35W bridge--who needs terrorists when there are Republicans"