Named after a member: Styracosaurus Rider.
Cerariders are vicious cephalopods native to the deep waters of Thanatos.
Cerariders resemble giant nautiluses, and are about 30 feet in diameter. They are named for having a pair of keratinous spikes on top of their heads, which are used to protect the head from harm, although this is obviously fruitless if a tusked leviathan, isonade or pelagic dragon attacks them.
Their tentacles are much longer than their bodies, but are rather thin. The tentacles can extend for 85 feet, perfect for catching nearby prey. Cerariders are usually brown or black in color, to blend in with the deep sea.
Cerariders are pack hunting carnivores, usually attacking in groups of 10-30 individuals. It is known that they will attack anything smaller than themselves, and even a few things slightly larger.
Tusked leviathans, isonades and pelagic dragons have been known to eat cerariders that come too close to the surface.
These are based on nautiluses, which IIRC are one of SR's favorite extant animals.