This is the Skeleton Flower. It is a white woodland blossom, whose petals become crystal clear once they make contact with water.
The Skeleton Flower, with the scientific name Diphelleia grayi, only grows in the wooded and moist mountainsides of cold regions, such as that of China, Japan, and the Appalachian Mountains of the United States. It can be easily recognized because of its huge, umbrella-shaped leaves.
Although this plant is seasonal, it can grow up to a height of 0.4 meters. Its flowers usually blossom starting mid-spring to early-summer. As the petals get soaked in water, they lose their white coloration. As a result, they look completely transparent. However, once they become dry, they go back to their original white color.
Watch the skeleton flowers in motion below: