Calcium
The shell or skeleton of a sea urchin is called a "test." The test is made up of plates that are fused together, forming a hard, protective structure. This skeletal framework provides support and protection for the sea urchin's internal organs.
Sea Urchin !
sea shell, sea urchin, small fish and others small sea spices
It's a sea urchin.
it has alot of protein.
The classification of a Sea Urchin is Echinoidea
Go back after you're done at Hollow Bastion. There will be a sea urchin. You have to mess with that to open the shell.
Sea urchins do not have an exoskeleton; instead, they possess an endoskeleton made of calcareous plates that form a hard shell, known as a test. This test is covered in spines, which are part of the urchin's body and provide protection and mobility. The structure allows them to maintain their shape and offers defense against predators.
sea urchin
A young sea urchin is called larva, pluteus (free-swimming stage), or juvenile.
It sounds like you might be describing a coconut. Coconuts grow on palm trees and have a hard, spherical outer shell with a hairy appearance that can resemble a sea urchin. Inside the shell is the edible white coconut meat and coconut water.
A sea urchin does move, but not very frequently.