The Zahgargak is a huge Rahi which was kept in the headquarters of the Shadow Proclamation. It was summoned by Kakamu once to fight Zev Raregroove. However, it was defeated and teleported back.
Many, many years later, it somehow found its way to the planet Kakamu and his family retreated to following the Uterio War. The planet's inhabitants captured it and used it to battle challengers in arena fights. Mocax defeated it by sticking his blades between its jaws, propping them open, then climbing inside and attacking it from within. He found two rotten Toa corpses complete with masks in its stomach, and dragged them outside. One of them was carrying the Spear of Fusion.