The seafaring people living on small islands in the Pacific Ocean, their high priests will transform into latex mermaids through a necklace passed down from generation to generation, providing divination for tribe members and escorting them on their voyages.
In history, there was a scientific expedition team passing by at this time. The expedition team rubbed its inscription from the necklace and, after being improved by professional magicians, obtained the latex manta ray magic used by Shanher

(reference from here(FA) and here(FA)