Shenyanniichuan
One of the many Jusenkyou Springs on the island, Shenyanniichuan is also known colloquially as the "Snakegirl" spring. Those affected by its waters most often appear like the naga of legends; a human torso, head, and arms with the lower body of a giant snake. However, more subtle alterations since a forked tongue, scaled body, changes in the eyes, etc. are within the realm of possible results from the spring.
Folklore
This spring is believed to be sacred to the Yuriban goddess Kikoutei; one symbol of the sun goddess being a coiled bronze snake. The fact that many blessed by the spring appear as golden, red, orange, or metallic hued snakes is widely considered 'confrimation' of this.