Marine echinoderm (8)
'marine echinoderm' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sea urchin that I've seen before include "Marine invertebrate with spikes" , "Shelled marine creature" , "Marine life form" , "Marine creature with near-spherical spiny shell" , "Marine invertebrate - enrich USA (anag)" .)
'marine echinoderm' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for starfish that I've seen before include "Astral aquatic animal" , "Well-armed customer" , "Has rifts (anag)" , "As swimmer" , "Heavenly marine animal?" .)