It... Is... ALIVE (again).
Here are a couple of vids showing an old (70's-ish) movie featuring a teen-age girl becoming invisible when she gets wet and returns to visibility as she dries off. Several scenes with process, even.
http://www.tudou.com/programs/view/VujnDw50Cts/
http://www.tudou.com/programs/view/3y0gxUsS9sc/