This strange little creature is actually  a sea urchin                                 Echinocardium cordatum and is founding sub- tidal regions in temperate seas around the world living buried 8-10 cms deep in the sand.This one was seen at Bithry Inlet.

It has tube feet [like Seastars] & uses these to  pass down the organic debris for food .

The mousy coloured spines trap air which help prevent asphyxiation of the  buried urchin.When they die & the spines are lost it is easy to sea the star shaped pattern on the test [ exoskeleton]….. occasionally the fragile ,white, heart shaped tests can be found washed up on our beaches .