Princess Shirahoshi, also known as the Mermaid Princess (人魚姫 Ningyo Hime?), is a giant smelt-whiting mermaid and the youngest of King Neptune's children. She was first mentioned by Pappug, claiming he knew her and even promised to introduce the Straw Hat Pirates to her when they arrived on Fishman Island (though later this is revealed to be a lie). She is also the current form of Poseidon.