Red Pencil Urchin

PLEASE NOTE: I found the remains of the urchin on the sea bottom. I will never kill or harm in any way any sea creature.
Those are the remains of the Heterocentrotus mamillatus, commonly known as the slate pencil urchin, red slate pencil urchin, or red pencil urchin. This is a species of tropical sea urchin from the Indo-Pacific region.