Nifetai
"When a child eats far more than you expect, watch them. More importantly, watch that they don't go off alone with anyone else. They might be a young Nifetai who could devour a person whole" - well-known advice among the Mu'o'a
Everyone among the Mu'o'a has heard of the ferocious and terrifying Nifetai, the Teeth of the Sea. They are shapeshifters who look just like a typical Kikipua, but have the ability to become gigantic, monstrous sharks, or even horrifying shark-kikipua hybrids. Given the opportunity, a Nifetai will devour whole communities to placate their appetite, leaving no traces behind except for bloodstains and screams.
Where They Come From
Nifetai are hatched from eggs, just like the Kikipua. When an adult Nifetai is preparing to lay an egg, they will transform into their Kikipua form and come ashore to observe a Mu'o'a village, specifically watching the communal nest. If the nest is ever left untended, or if those watching the eggs fall asleep, the Nifetai will sneak into the nest and replace one of the eggs with their own. If anyone catches them doing it, they will usually shift to their half-shark form and attack, creating such chaos that nobody afterwards can be sure which egg was left behind by the intruder.
When the egg hatches, the infant Nifetai is indistinguishable from the other hatchlings, and remains so for several years, until their appetite suddenly begins to grow. The child will start eating more and more, and never seem to be full. Stories are told of half-grown children devouring a feast intended for the whole community, and still asking for more. Over the course of a few months, the Nifetai can eat every bit of food a village contains and can produce, and will even eat non-food items such as stones and wood. Attempting to deny food to the Nifetai child will cause them to fly into a rage, which is when their true nature usually asserts itself.
The Transformation
Anger and hunger trigger the change in the young Nifetai. Their body swells and grows, and their mouths gape open, sprouting rows of sharp teeth. A Nifetai in their half-shark form is immensely strong and swift, and can shred an adult Kikipua in seconds, consuming their corpse and leaving nothing but a red stain behind. Once the first transformation has occurred, the Nifetai will go on a rampage, attacking and devouring every creature they encounter.
Once the Nifetai has eaten everything and everyone it can find, it will go to the sea. It is called there, and it will not stay on land longer than a day or so after the change. It hurls itself into the water, where it can complete the transformation into an enormous and monstrous shark. It then swims towards the open ocean and vanishes, leaving the survivors of the massacre to grieve and rebuild.
In the Sea
But this is not the end of the Nifetai's story. Out in the ocean, it continues to hunt and devour anything it can, and it never forgets the taste of Kikipua flesh. As it matures, it learns how to control its transformation, and can shift back into the shape of a Kikipua. Sailors have many stories of resucing a stranded Mu'o'a far out in the ocean with no other ships in the area, only to have it suddenly shift into the horrifying half-shark as soon as it is on board. Other stories are told about ships left adrift with no survivors, only bloody decks left behind.
Secret Feasts
Before the final rampage, many young Nifetai will be driven to seek out food by any means necessary, but will attempt to keep their feasting a secret. They will sneak into the community food supplies to devour them, and will hunt and fish as much as they can to sate themselves. They are also known to lure anyone they can to meet them in private, especially the younger and weaker members of a community, so they can kill and devour them without any witnesses. One of the best signs that there is a Nifetai in the village is when members of the community suddenly vanish without explanation. Of course, at this point any confrontation is likely to trigger the creature's transformation into its adult form.
Nifetai Villages
There are rumors that the Nifetai do not spend all their time as sharks in the sea, but have villages of their own in remote places. Those who tell of these places describe finding a village that seems like any other Mu'o'a community, but with strange and hungry looking villagers who have unsettlingly sharp teeth. According to the stories, those who accept the hospitality of the Nifetai will regret it.
The Nifetai's Weakness
A Nifetai is capable of eating and digesting almost anything it encounters, but there is one substance that is poisonous to it - gold. Even then, not any golden object will bring down the monster. It must be something that is sharp or pointed, so that it will lodge inside the creature's stomach and remain there long enough to rot the creature from the inside. The most common story told of this involves a golden fork, but any golden object that it cannot get rid of will eventually destroy the creature.
me: ~opens article~ "oh, the dude on the cover image looks cool, almost friendly. Might become to have a beer and trade stories me... after reading article: "hmm... no. No beers with that guy, even if he does look like a Samoan fused with a shark. I'll pass. I eat shark, not the other way round"
Yeah, he’s not a friendly fellow!