And once again you missed the "constant contact" bit... :| First of all, when a person is in constant contact with water, their body becomes wrinkly because the dead keratin cells on your hands absorb the water, but the living cells don't, causing the skin to wrinkle as the dead cells try to expand while being restricted by the attached living cells. If water is in constant contact with a rock, such as a pebble in a stream, the moving water wears away at the pebble until it's smooth to touch. On a large scale, a winding river can, over the course of time, cut its way through a mountain or even flat surface an, after it's dried up, become what we call a "valley".
So, constant contact creates a "washing away" effect on objects, washing away a surface to create a valley, or to smooth a stone, or even to wash away dirt on one's hands. It also, specifically on humans and other living beings (possible), causes wrinkling in skin cells, specifically dead keratin cells.
Do you understand the consequence of constant contact with water (the "wash away" effect is mostly what suiton focuses on, by using water to crash through things or create rivers)?