Spinax

Spinax was Maxilos' Energy Hound, and had been accompanying Maxilos for a very long time. He is referred to as an Energy Hound because he could track down the location of anything, even a single mote of dust, by sensing its energy. He was also amphibious because of the Pit's mutagen. Greg Farshtey has also stated that Spinax will fight the Makuta of Metru Nui. Aside from that, nothing else is known about this mysterious creature.