GEORGETTE DOUWMA / Parasitic urchin snail (Luetzenia asthenosomae) on Fire urchin (Asthenosoma varium) laying eggs. Bali, Indonesia.

Juergen Freund / Blue starfish {Linckia laevigata} close up of arm with parasitic snails {Thyca crystallina} attached, Indo-Pacific

Nature Production / Parasitic snail {Stilifer akahitode} in arm of Sea star {Certonardoa semiregularis} (part of the arm is artificially cut) Japan

Doug Perrine / Parasitic sea snail {Thyca crystallina} camouflaged on arm of blue sea star {Linckia laevigata} Mabul Island, Sabah, Borneo, Malaysia

Fred Bavendam / Fire Urchin (Asthenosoma varium) that is host to a pair of Coleman's Shrimp (Periclimenes colemani) and parasitic Snails (Leutzenia asthenosomae), Bali, Indonesia

Fred Bavendam / Limpet (Thyca crystallina) living on coral surface and the Blue Sea Star (Linckia laevigata), Manado, North Sulawesi, Indonesia

Constantinos Petrinos / Parasitic snail {Leutzenia asthenosomae} on toxic Sea urchin {Asthenosoma varium}