Who needs seahorses? This large sub-gastropod is a commonly used riding animal by the Gillian race.
Slaugeists are part of the solariformes ("Solar-Users") group. Unlike most of their star brethren, their solar energy is barely used, mainly providing a source of light for their limited vision. As such, they can last for days without sunlight in depths most creatures would dare not attempt to enter. Preferably, Slaugeists skid across the seafloor instead of swimming, as it requires less energy to remain afloat. The Gillian's trek onto land proved successful for these lumbering giants, as their amphibious nature plops them down on their belly on land as it did on the seafloor.
Having such a slow, dimwitted lifestyle resulted in the Slaugeists having low metabolisms. A single meal can last a Slaugeist weeks on end without food. Their primary diet consists of sea algae/grass and Pebejellies, of which their Gillian caretakers provide them with. Other food sources include other soft-bodied invertebrates that the creature catches with its large limbs. This diet and slow star cycle for a solariforme has guaranteed a long life for the Slaugeist species, longest recorded alive being 1000 years.
While no way aggressive, Slaugeists will not hesitate to batter enemies with its large frontal limbs. The power of which is said to be equivalent to being hit by a grizzly bear's paws. Some Gillian owners have trained their mounts to perform a short range ramming attack, although it drains their strength much more quickly. It isn't favored to kill a Slaugeist, as like all other solariformes, their stars explode on death. But if such a case were to find a dead Slaugeist, one would find a plentiful supply of congealed fat reserves and aged meat.
An adorable Paradox.