Going with the Wind
Carried by wind currents, Jellies seemingly drift through the sky;
unlike Air Rods, they cannot go against the current and are not agile. Instead of relying on speed and keen navigation skills, they depend on their great size to survive. There are few dangers and predators for Jellies. In fact, their greatest threat is air pressure. Unable to withstand even slightly higher pressures, Jellies burst if blown to low altitudes. Sensitive to pressure changes, they may alter their forms to glide upward or slow down, but strong storms may overcome them regardless.
Casting a Wide Net
Atmospheric Jellyfish are predominantly filter feeders—animals that open their mouths wide and eat whatever gets caught inside! Jellies get most of their food on sunny, breezy days when atmospheric beasts fly with the wind and atmoplankton wriggle towards the sun. On less ideal days, their sticky arms catch prey that passes by. Lightweight, the arms gently float behind it like a kite's tail. Some high sky animals are lured to the arms by scent, color, or their movement; drawn near for a nibble or out of curiosity, smaller animals may find themselves stuck in a tightening coil. While unable to move very much, when Jellies detect prey, they can snap an arm upwards in hopes of a catch. Arms curling upwards like a spring, morsels are slowly brought into the Jelly's mouth, where they are digested in a pool of acid.
Jellies filter feed when they detect prey all around them. Inflating with air, they flatten their limbs and curl them forward around the head. Jellies have two mouths that are always open: a smaller one by the arms (the "beak") and a larger one on top of the head (the "maw"). While the wind may blow food into its current-facing beak, its maw catches those ahead. Opening wide, held air is forced from the beak, launching the animal forward. Arms trap animals and particulates, then carry them towards the growing vacuum. The gulp of air passes through a thick, stringy, sticky carpet; the gooey filter traps food bits but allows air to flow past and outside. Closing its maw and relaxing its arms, the Jelly swallows; a chitinous, flat scraper runs down the filter, pushing food into the stomach.
Atmospheric Jellyfish must float and propel endlessly, as none of their bodily functions work without air moving through them and activating their organs. Food, however, requires a period of dormancy; as the creatures float dormantly, meals digest.
the Floating Hatcheries
The stratosphere is the breeding ground of all Atmospheric Jellyfish—and, like most high sky animals—they are bright and colorful when romance is on their mind. During courtship rituals, the entirety of a female Atmospheric Jellyfish's body pulses, bubbles, jiggles, and dances with eye-catching color; their heads neon bulbs and their ribbony extremities writhing with beams, flashes, or speckles of light, they draw the attention of males. Visible to the human eye, these displays are beautiful yet menacing, like a high-tech UFO. Atmospheric Jellyfish, can only vaguely sense the entrancing lights they produce; they are much more attracted to the ritual's other qualities.
Courtship exhibitions generate not only light but heat, luring in a variety of prey; the activity also creates a lot of motion, enticing nearby Jellyfish. The combination of light patterns, vibrations, and heat is a clear signal to males. Those interested slowly float towards the larger females; if both like what they see, their tentacles entwine, and her light show ends.
Not very mobile flyers, the couple fills with air and balloons upward. Reaching the drier, calmer middle ground of the stratosphere, they release gametes through a multitude of pores on their head; this type of reproduction is called spawning. Weightless, floating, fertilized eggs spread out in a cloud; they clump together in small balls over time, forming clustered hatcheries. Their job done, the pair awkwardly flip upside down and release their held air, propelling back down into the atmosphere. Their offspring are safe above; those who would eat them almost only exist below—and some, like the Sky Serpent, specifically seek mating Jellyfish and their young.
Jellyfish courtship displays occur seemingly randomly, confined neither to a time of day, season, or atmospheric condition. The displays may last several weeks, especially for rare species seeking a mate. As females cease eating during courtship, they may perish if a suitable male isn't found.
