Cassiopea xamachana, commonly known as the upside-down jellyfish, boasts a significant medusa phase, reaching about 30cm in diameter, resembling more a sea anemone than a conventional jellyfish. Its name stems from its unique behavior of settling on the seabed with its frilly tentacles pointing upwards. The saucer-shaped umbrella is relatively flat, featuring a distinct central depression on its upper surface, facilitating attachment to the seafloor via gentle pulsations. It possesses eight oral arms elaborately branched in four pairs. Typically appearing greenish grey-blue, this hue results from embedded zooxanthellae algae within the jelly body and arms. The mobile medusa stage exhibits dioecious characteristics, while the polyp stage is sessile and small.