That is essentially what a jelly fish is. To paraphrase another comment quoting wikipedia: "Most jellyfish do not have specialized digestive, osmoregulatory, c

That is essentially what a jelly fish is. To paraphrase another comment quoting wikipedia: "Most jellyfish do not have specialized digestive, osmoregulatory, central nervous, respiratory, or circulatory systems." and, "Jellyfish have no brain nor central nervous system."