Pua Tu Tahi is a sea monster from Tahitian mythology. It is said to resemble a giant clam, and reside in the deepest parts of the ocean.
Pua Tu Tahi appears in the story of Rata, a legendary prince of Tahiti. Rata’s uncle, King Tumu-nui, and his father, Vahieroa, were swallowed by Pua Tu Tahi while travelling to the Pitcairn Islands. As a result, Rata became king, and vowed revenge on the monster. Rata and his crew were also swallowed by Pua Tu Tahi, but cut their way out with their spears.