Class Scyphozoa, commonly known as jellyfish, belongs to the phylum Cnidaria and is known for their characteristic bell-shaped body. Synonyms for the term "Class Scyphozoa" include jelly, jellyfish, medusa, sea jelly, and sea nettle. These marine creatures are carnivorous and possess stinging cells called nematocysts, which they use to catch their prey. They come in a wide range of sizes, and some can be as small as a fingernail while others can grow as big as a human. Scyphozoans are essential in maintaining the balance of marine ecosystems and play an important role in the food chain. Their unique and mesmerizing appearance has made them popular in aquariums and as a subject for scientific study.