Horned sea stars have multiple humps on its surface and a large hump in the middle. It lives in temperate/subtropics regions of Indian Ocean and West Pacific Ocean south of AmamiOshima. It can grow up to be 30 cm in diameter. There are many variations. Some are red and some are white. Its body is very hard and it is relatively heavy.

In AmamiOshima, they can be observed in shallow sand areas where seaweeds grow.