The Dweller in the Deep was a massive, beastlike underwater Rahi specimen which lived in the sea beneath the Great Temple. Its preferred prey was Great Temple squid, being their natural enemy.[1, 2] It had large, sharp teeth.
The Dweller in the Deep was long thought to be a myth by Ga-Matoran and was said to live at the very bottom of the sea. It was believed to be the only natural enemy of the dreaded Tarakava serpents. Toa Nokama confirmed this creature's existence when she retrieved the Great Disk from its jaws. When it surfaced in pursuit of her, witnesses saw only a massive, sleek shape and jaws that seemed wide enough to swallow the Great Temple whole. It since returned to its home underwater.