"Cymbal Bubble Snail" (Haminoea cymbalum)
…a species of haminoeid bubble snail (Haminoeidae) that is widely distributed throughout the Indo-Pacific, reaching as far east as Hawaii and as far west as the Indo-West Pacific. Cymbal bubble snails are chiefly diurnal and are mainly seen in tide pools and other rocky habitats. They are also herbivores and feed mainly on algae. If threatened H. cymbalum can secrete a metabolite which is a deterrent for many carnivorous fish.