Magi-clam

The magi-clam is an undersea creature that fashions coral and produces pearls. The different variants grow to lengths between 10 cm and 2 m and come in a variety of colours.
As magi-clams breathe in and out nutrients of the seabed, they also breathe in and out magic around the seabed. Mermaids use this to communicate simple tasks to them, such as maintaining the coral of the palace. Magi-clams have always had a relationship with coral. To hide when young and still forming their shells, they sit in, on or under a piece of coral and match the coral to the shell colour and texture they are forming. Although magi-clam themselves do not glow in the dark, they can activate glow in the dark in many types of coral.
Mermaids have cared for and cultivated a number of magi-clams around Coral Palace. Many help clean the floors of the palace, moving at a pace of 20 cm per month. Such magi-clams will often produce 'wild pearls,' made of twisting colours and cracked shapes. These are turned into charms for mothers who have lost their own children. Some of the larger clams have become part of the palace's structure, melding with the coral and keeping it specified textures and colours, as well as maintaining the lighting.
There is also a magi-clam farm, specifically for producing a variety of pearls. Mermaids feed irritants to the magi-clams, then sing with a magically infused voice that spreads through the currents to reach all the magi-clams in the farm. The singing signifies what type of shape, colour and lustre the pearls are to be. Many of the magi-clam can be seen lightly swaying their shells in the currents (though still not letting go of their attached spot on the seabed a sign of happiness.
Once a magi-clam dies they either give themselves to the ocean (by lifting their foot for the last time and allowing the deep-sea current to take them away from Turien) or hand themselves over to a Mermaid. If handed to a Mermaid, their shells are often used for charms, with the first charm made and kept by the Mermaid the magi-clam gave itself to.

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