Purple-shelled clams, called cherrystone clams or mercenaries, are a species of clam commonly found along the east coast. Small cherrystone clams start out as white when small, but turn purple as they grow larger.
Octopuses live on the bottom of the ocean. They eat by pulling small animals into their mouth with their tentacles. They eat clams, fish, and clams. They paralyze it by injecting it with ink and then tear it into pieces.
Clams, like most mollusks, also have open circulatory systems, which means that their organs are surrounded by watery blood that contains nutrients and oxygen. Clams eat plankton, and they themselves are eaten by small sharks and squid
Moon snails drill a hole in the shell of clams and suck them out. If you walk the beach you will find clam shells with small round holes drilled in them near the hinge. That is the work of a moon snail.
Fortunately most of the things, including clams, are dead when we eat them. Except for oysters, of course. Oysters are .... different. If it is well prepared (cooked, roasted or whatever we do with clams) and you didn´t find it on the beach, rotting and a bit like goo ... why not?