I just recently finished watching the film *Moana*. The plot includes the Realm of Monsters, complete with upside down giant crabs, a shape-shifting demigod with a magical hook, a giant lava monster, a giant mother island...

![Te Ka](https://i.ytimg.com/vi/hbf6FR6LZps/maxresdefault.jpg)

Are these based on an established mythos, such as one of the Oceanic mythologies?