Spondilus

Growing up to 4 m in length, and up to 1 m tall, these large reptiles can be found only in the Underdark underlying the remote city of Ka Hei. These strange creatures use their long necks to reach into the small cracks and pockets for food which their larger body can't get into. Small cracks that even their heads can't reach into can be pried open using a pair of strong claws on their front feet. Spondilus are naturally omnivores, but their diets consist almost entirely of lichen and mushrooms which grow in the Underdark.
Although relatively small, they are slow-moving, and spend most of their time eating to sustain themselves.
Their strong claws have a second, equally important use. In addition to a series of small spikes along the bottom of their feet, their claws allow them to cling to any cave surface, up to and including hanging upside down.
The Pu Yi of Ka Hei graciously welcome the Spondilus into their city. Although they typically don't directly interact with the creatures, they are warmly viewed as pest control or cleaners. Spondilus can be found throughout the city, typically hanging from the ceiling or randomly crawling through someone's house looking for food.