Shellfish is a very distinctive animal with a fairly hard shell. Many who like to find these animals on the beach and there are also like to look for it at the restaurant, aka make it delicious food that inspires nyamm nyamm nyamm. Seashell shells are also widely used as jewelry and other trinkets.
The unique thing about the shellfish is that it does not seem to feel pain. Just so you know, the usual shell we eat it (especially those who usually consume raw shell) is most likely still in living condition. But because shell life is low, they may not have the pain and the ability to fight when we open their shells and devour their flesh.