A parasitic species which finds skeletons of other creatures and uses them like shells. They tend to resemble the musculature of what the species' skeleton they're in. As they grow they search for larger bone cages. They are most famous for their inhabitation of skulls but they can be found in bug carapaces at their smallest and gorilla ribcages at their larges, though this is a rare sight to see. They prefer skulls though for they provide the most protection which is where they derive their name.