Named after a terrestrial flower, the anemone, the sea anemone is a group of ocean dwelling animals of the order Actinaria. As a cnidarian, it is closely related to coral and jellyfish. The anemone is a (usually) solitary polyp with stinging cells (cnidocytes) in its tentacles. These stinging cells serve to paralyze and capture prey, which is then moved by the tentacles to the mouth for digestion inside a central cavity.
Other close relations to the sea anemone are the solitary, tube-dwelling anemones and the hydras.