Jellyfish always much greater than the Lion's Mane, whose bell diameter can reach . The rarely encountered deep-sea jellyfish "Stygiomedusa gigantea" is another candidate for "largest jellyfish", with its thick, massive bell up to wide, and four thick, "strap-like" oral arms extending up to in length, very different from the typical fine, threadlike tentacles that rim the umbrella of more-typical-looking jellyfish, including the Lion's Mane. Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae
Jellyfish Lake in the afternoon. The moon jellyfish do not have an organized horizontal migration pattern. At night they migrate to the surface presumably to feed. The copepods that make up a significant portion of the moon jellyfish diet in Jellyfish Lake also migrate to the surface at night. Beginning in about the fall of 1998, a precipitous decline in the golden jellyfish medusa population was detected in Jellyfish Lake. By December 1998, the medusa population had declined to zero. Based on their extensive investigation of the disappearance of the golden jellyfish medusae, Dawson et al. determined that the most likely cause