Menexene

Menexenes are a sentient species of gas giant dwellers that inhabit their homeworld's liquid metallic hydrogen core rather than its upper atmosphere. Their biology is therefore based on magnetohydrodynamics (MHD) rather than chemistry.

Anatomy & Physiology
The Menexene viscera - its "core" - consists of an ellipsoid around 30 meters (98 feet) long and 22 meters (72 feet) wide, massing around 1,000 metric tons (1,100 short tons; 2,200,000 lbs). An outer layer called the pallium, a complex structure of magnetic fields and flows, surrounds and protects the viscera, also serving as a manipulator and sensory organ. While there is no hard boundary between the pallium and the outside world, it is usually around two meters (6.5 feet) thick at the thinnest, bringing the alien's total length to around 34 meters (112 feet). The pallium also bears many constantly twisting and curving spines in an irregular pattern, some of which are as long as 20 meters (66 feet).

The viscera, unlike the pallium, is symmetrical, possessing order twelve radial symmetry. The outer layer contains generators and capacitors that produce and interact with the pallium. Menexenes have no "front" or "back," but they do have distinct ends, the face and the spinneret. The slightly pointed spinneret produces webs, while the rounded face contains the feeding and reproductive organs. At the very center of the viscera lies the brain.

Diet
Like all organisms in Menexenos' core, Menexenes feed off magnetic energy and store the energy using capacitors consisting of helium-neon membranes, as helium and neon are the only elements that do not ionize in their environment. Menexenes are consumers rather than producers, and so they must hijack the energy stores of other creatures by forcibly tapping into or inducing fluid flows to feed upon. They also consume various elemental impurities, mostly helium and neon. However, with technological aid they can extract energy directly from their homeworld's convection currents for feeding purposes without having to prey on other organisms.

Reproduction
Menexenes reproduce sexually. A male and female Menexene slowly share their palliums, with their viscera meeting mouth-to-mouth after one to two hours. When the two meet, the male transfers a haploid copy of his genome to the female, and sex immediately ends.

The offspring gestates in the inner layers of the mother's pallium, directly touching the viscera. After one month, the offspring has matured enough to leave the pallium for short periods, but must return for feeding and care. This second stage lasts for another one and a half months before the offspring separates permanently, by this time about seven meters (23 feet) across. The offspring matures to adulthood over the next nine years.

Homeworld
Menexenes inhabit Menexenos, the fourth, largest, and outermost planet in their solar system. It masses 0.9 Jupiter masses (about 300 Earth masses), and is broadly similar to Jupiter in terms of temperature, composition, and structure. It orbits its parent star, a yellow-white dwarf (spectral type A5V) at a distance of 12 AU.

Menexenes do not and cannot inhabit the upper atmosphere. Instead, they live in its vast, deep ocean of metallic hydrogen, at temperatures of 10,000 K (10,273 C; 17,540 F) and pressures of 200 GPa (2 million atmospheres).

Technology
All Menexene technology is MHD "biotech" in one form or another, since no other structure can exist in their environment. Most Menexene structures are derived from their own webs and Menexenos' native worldtrees. The largest of these structures are three immense networks that cover the entire habitable region of the core. These nets are devoted to food/energy, transportation, and telecommunications.

Menexenes never developed, and never could have developed, any kind of space travel, as neither they or their technology can survive outside the tremendous heat and pressure of their home. Some Menexenes do live and travel offworld, but they rely completely on Terragen technology gifted to them for this purpose.