The Moai Statue, also known as the Easter Island Heads, is an archaic naturally spawning structure based off the real-life Polynesian statues on Easter Island carved between 1250 and 1500 CE, and which still exist today.
It can be found rarely on beaches and surrounding biomes, sometimes slightly submerged or in water. It was added in Build 7.3, the 'Dinosaur Renaissance' update.
They are very large, at 15 blocks tall and 5 blocks long, but can sometimes spawn with up to half their body buried in sand. They also sometimes spawn with a clay hat. It somewhat resembles a minecraft villager.