Hitodeman

Hitodeman is a golden-brown starfish-like Pokémon with five appendages. These appendages surround an exterior organ called the core. The core resembles a golden metal casing with a red gem in the center, which is held in place by a golden ring looped around Hitodeman's lower left point. If any of Hitodeman's appendages are lost or eaten by predators like Lumineon, it is unharmed and can grow them back with ease provided the core is still intact.

When the sun goes down, the core glows its brightest. Many Hitodeman will float from the seafloor to the surface and align themselves with stars of the night sky as their core flickers, displaying a connection with the celestial bodies of space. The anime has shown that if Hitodeman becomes weak, its core will grow faint and flash slowly. During the ends of summer, groups of Hitodeman tend to gathered while lighting up in a steady rhythm. Hitodeman can be found at the very bottom of the ocean on the seafloors.

(Source: Bulbapedia)