This core is the first part of a Ravorbis coming into existence. Once it gathers enough surrounding magic, it will form a small spirit around the orb. At this stage it is not much more than a head, capable of consuming more magic. This initial form is referred to as the spirit orb. 

(Character on the example belongs to Katarsys)

If a Ravorbis consumes enough magic, they will eventually use it to form themselves a body, a shell. A shell takes the form of a mostly humanoid body, but will have at least one tail-head that looks like the spirit orb form protrude from it, as well as have their orb embedded somewhere on their body. Sometimes, the spirit head will also have it. The shell can display features present in the head, such as spikes or fins, but they are kept small on the body. After all, it serves to both blend in with their surrounding species, and to attract potential prey - beings that hold magic.