It is made of an annelid like an earthworm (Sipunculus nudus, which lives in beaches and mudflats in the estuary area). Because of its high collagen content, it becomes jelly-like when boiled. It can be dug in the desert beach sand in the coastal areas of South China, so dig hard, because it will drill (flee for life) deep and starve for a day, or just cut it open to remove the internal organs and put some water in the pot to cook. I know it's mushy, take it out and pour it in a mold to cool it, and then add some seasoning to eat it ~