Just recently I have started to play around with painting on the surface of water. It can be very challenging but there are rewards. Once you have pulled your canvas out of the water, the paint grabs onto the canvas creating the craziest abstract designs with such fluidity.
Here is a recent piece I did of a peacock. I tried to get as much of the pattern as I could on the surface of the water, before I submerged it. Then I went over with a tiny paint brush and tweaked it to my liking.
Sidenote: if you try this, make sure you are not under a maple tree in the fall . I have to fish all of the leaves out before each dip, lol.