Turritopsis dohrnii (the immortal jellyfish) belong to the phylum Cnidaria along with other jellyfish, corals, anemones, and sea pens. The distinguishing feature of the phylum Cnidaria is cnidocytes, stinging cells that play a role in capturing prey and providing protection from predators. Among the phylum Cnidaria, the immortal jellyfish belongs to the class Hydrozoa. Hydrozoa’s distinctive feature is a complex life cycle that alternates between the benthic polyp and the planktonic medusa (je