Shadowy depths lie beneath Mata Nui—ancient, silent, and unknowable. And sometimes... something rises from them.

Glowing only when it intends to, the Mahri Mackerel glides effortlessly through the black waters, a phantom in the deep. Its bioluminescence flickers like underwater lightning—sharp, fleeting, and always just out of reach. To the untrained eye, it is invisible. To its prey, it is unknowable—until it is far too late.

These elusive beasts, born of shadow and pressure, rarely rise toward the surface. Even the Ga-Metru scholars, who study the seas from the safety of stone balconies, speak of them only in whispers. When one is sighted near the surface, it is a sign—something stirs in the depths. A greater shadow, buried far beneath the island, calls to them. And they listen.

"Careful, Kai!" shouts Kotu, a Ga-Metru Rahi tender, her voice echoing off the stone pillars of the dock. She grips the edge of the pier, eyes wide with a mix of concern and awe. "We don’t know what’s down there!"

"It’ll be fine, Kotu. Hold your Rahi," Kai calls back, smirking with the casual confidence of someone who’s spent more time on water than land. A seasoned sailor of Mata Nui’s silver-blue coasts, Kai has charted these waters for years. Storms, sea Rahi, even the occasional rogue Tarakava—none had ever fazed him. Until now.

For all his bravado, Kai can't shake the feeling. The waters are too still. The air, too heavy. And then—there. A glimmer beneath the surface, then gone.

The Mahri Mackerel is massive. Silent. Curious. And close. So close that when it shifts beneath the boat, the water gently swells, causing Kai’s vessel to list ever so slightly. Just enough to set the lantern swaying. Just enough to make him pause.

Explainable or not, a creature of this size could upend even the sturdiest craft before its presence is fully known.

Whatever calls the Mahri Mackerel to the surface... it isn’t done yet.

Another creature inspired by the use of unique and marbled elements, this Mahri Mackerel uses the base elements from the two Bionicle Barraki sets; Takadox (Set #: 8916) and Nocturn (Set #: 8935). Each set comes with a few cyan transparent elements infused with glow in the dark strands. This makes for a very unique color, and is only seen with three different Bionicle sets where a total of four different elements exist in this shade, three of which are used here.

The mask used on Takadox reprises itself here in this design, utilized as an upper lip in the MOC, and the eyes constitue for nostrils where glow in dark minifigure piraka spines (Part ID: 55236) sit. The mask from the Nocturn set sits backwards beneath this to form a chin, while large 4x4 rounded plates and transparent dark blue domes fill in the gaps for larger, alien type eyes in this deep sea rahi. Utilizing five of the knee/shoulder armor that is seen in both sets on each side of the fish, I created a scale pattern. This pattern is one that was held and laid out prior to anything being connected seeing as these elements are hard to find and very expensive sourcing them in greater quantities. I used Bohrok eyes to fill in some of the smaller gaps in transparent light and dark blue with the frame of the build being created from blue to give the outer shell a similar undertone of shades, because I knew the armor elements would result in some hairline gaps throughout the model.

Nokama Metru's mask is another unique shade of transparent blue only appearing in two sets; Toa Nokama (Set #: 8602) and Dalu (Set #: 8726). This different shade of blue is one that I decided worked will for fins, and paired with some Flame/Vapor Trail elements (Part ID: 1995pb02) in the tail added to a nice level of transparency within the appendages of the MOC.

The added bonus of the elements having the ability to glow in the dark, and the added glow within the mackerel's eyes and whiskers resulted in a surpisingly bright model when illuminated! This is something that drastically surprised me, as I have always little faith in most glow-in-the-dark items, yet the elements used altogether was astounding! Every deep sea creature deserves a powerful, creepy glow!