Tidalem

The tidalem, also known as the ghost leviathan, is a species of water elemental spirits. Its juvenile forms, commonly called dropblobs and nagaruga, are considered quite common.

Appearance 

An adult tidalem can measure from fifteen to sixty meters in length, absolutely exceptional dimensions even for elemental spirits (with the exception of puripyres), which are dictated both by the age and the diet of the spirit.

These enormous creatures have a semi-transparent body, of an iridescent and variable blue color, which allows the silvery "bones" to be seen. In reality this scaffolding, which mimics the shape and arrangement of the skeleton of a vertebrate, is made almost entirely of mercury (also known as quicksilver) and is held together by the pressure of the rest of the body, therefore it has a completely different function compared to a real skeleton.

The head is relatively small and stands out on the "hood" composed of two large folds, similar to the one that cobras form by inflating their neck when they want to threaten an enemy. The hood is permanent, however, and contains the only truly solid part of the tidalem's body, a deposit of calcium, carbon and chitin that during one of its juvenile states constituted a real shell, not unlike that of an alligator snapping turtle in function and shape, which protected the energy center of the spirit.

They have only one pair of limbs, the arms, which end in strong, clawed hands, with an iron grip; however, the arms are remarkably small when compared to the overall size of the tidalem, and have no significant use in locomotion.

The eyes, bright and large, are perfectly round and can be of various colors, from yellow to blue and even, more rarely, red/orange. Unlike lesser spirits, the color of a tidalem's eyes has no correlation to the type of energy center the spirit has.

Life cycle

Tidalems are born from eggs that are laid near freshwater streams. When they hatch, the paralarvae look like a dense drop of water about fifteen centimeters long and are called dropblobs. 

As they grow, the dropblobs collect limestone, and other minerals, in a deposit on their backs, becoming increasingly opaque.

Soon, when they reach forty centimeters in length, the dropblobs begin to molt: two legs emerge from the front of their body, the back part elongates into a tail, while their "shell" becomes increasingly majestic and heavy, protecting them from predators and also helping them to hide from prey. Their shell is in fact irregular, with spikes and small fractures along the surface, as well as a rough surface, and favors the growth of moss and algae. 

In this second stage of life, this creature is called a "nagaruga", a cross between the words "naga" (serpent spirits that live in the water) and "turtle" in italian (tartaruga).

Nagarugas have a long tail, just like nagas, but instead of ending in a point, like that of snakes, it ends in a tail fin not unlike that of a large fish. Nagarugas spend most of their time motionless, half-buried in the mud, and when they curl up it is almost impossible to see them: they look for all and for all a boulders covered in plant matter. After about forty years, nagarugas have accumulated enough energy to be able to undertake the journey that will lead them to their final form: that towards the sea. Using their powerful tail, they descend along the rivers until they reach their mouths, from which they will then flow into the salt water basins. 

This is the most dangerous part of their journey, as the seas (and oceans) are filled with spirits that are bigger and stronger than them, capable of breaking their shells as if they were made of wet sugar: the nagaruga will have to use all their camouflage skills to escape predation and at the same time be able to "steal" enough prey from the territories of spirits bigger than them to grow. In this phase, their body will gradually become too large to be hidden by the shell, which will remain as a vestigial residue on the creature's neck, where it will be covered by its "skin" to become an internal component, like a cuttlefish bone, and will transform into the structure of the characteristic hood of the adults. 

Finally resembling sea serpents, at this stage of life the creatures can be called "tidalem". Young tidalems are agile and fast, slim and slender, and manage to survive thanks to their speed of movement, as well as the ability to hide in holes in the ground that are dug by scylloids, with which they sometimes bond in curious partnerships.

Adult tidalems are instead immense and placid creatures, that do not associate with other tidalems and establish a large territory. 

They have very weak limbs, compared to the immense weight of their body, they are therefore unable to walk in the true sense of the word; on the other hand, in water they are extremely agile, thanks to their long body that ends in a powerful tail, which allows them to move at will and to be able to maneuver quickly and effortlessly. They can no longer hide in any cavity, being enormous, but they do not need to: their strength is unrivaled in the oceans, being the tidalems the largest sentient spirits of the aquatic environment.

Reproduction 

Tidalem reproduction usually occurs during periods of great prosperity, which allows them to feed themselves sufficiently. When they are ready to reproduce, tidalem enter a so-called "flame" state, as happens with other spirits, in which their overabundance of energy becomes visible thanks to an emanation of a luminous aura, which arises around their heads and hoods, similar to fire. 

Flaming tidalem will leave their territories and even the water, hovering in the air and moving like oriental dragons, floating in search of other flaming tidalem, with whom they will mate in pairs. Once both specimens have been fertilized, they will move by flying inland, where they will lay their eggs in clusters buried in sandy or muddy soil, near waterways. 

A single specimen can lay from six hundred to twelve hundred eggs, depending on the size of its body and the amount of food it has ingested before starting its reproductive journey. 

The clash between puripyres and flaming tidalems has been documented several times near rivers. Especially if the clash occurs on dry land, the puripyres often manage to gain the upper hand. It is not an attempt at predation, but a clash for resources: where an area is too richly populated by dropblobs, the paralarvae of tidalems, it is transformed by their auras, and by their action, into a humid territory where the puripyre young, the fatini, will struggle to survive. Furthermore, the dropblobs tend to grow and become strong more quickly than the fatini, entering into direct competition with them and even preying on them. 

Once the laying is finished, the tidalems will return to their original territories and will remain there until the next reproduction cycle. 

When a tidalem dies, its internal parts are no longer pressurized, and as a result its mercury skeleton disintegrates and mixes with the rest of its tissue, making it poisonous and completely inedible. Its flesh loses its compactness after just a few minutes, dissolving into a poisonous fluid. 

The death of a tidalem would therefore constitute a true ecological disaster, were it not for the fact that the adults, mortally wounded, sick, or in any case close to their end, voluntarily go near an area where eggs have been laid, or where countless dropblobs are already present, who will hasten to consume them. The mercury present inside a dying adult will then become the mercury that makes up the skeleton of a young dropblob, thus also offering it further protection from predators: the dropblobs that have fed on an adult tidalem exhibit a silvery back, which reveals their toxicity to other spirits in their environment. 

Paralarvae that have a rudimentary mercury skeleton are also called "death drops" or "silverback droblobs".

Habitat 

Adult tidalems live in large bodies of salt water, whether they are seas, oceans or even large lakes. They are cosmopolitan and can be found even in very cold areas, such as the Arctic Circle. 

Diet 

Tidalems are omnivorous, but the basis of their diet is medium-sized spirits. They use very different hunting strategies, at different stages of their life, but they always have a fairly high success rate. 

Tidalems perceive sound vibrations at great distances and have an acute sense of smell, they can also perceive very weak electric and bio-electric fields generated by the activity of their potential prey. 

Some tidalems, especially the very large ones, are extremely sedentary and prefer a markedly planktophagous diet, that is, made up of small aquatic organisms that live in large groups. During the reproductive period of the small spirit-fish, they can also ingest clouds of eggs that are released into the water. 

The most planktophagous tidalems develop special structures in their bodies, called "pads", which serve to separate water from prey. These pads are extremely similar to the modified gill rakers of the whale shark, or the manta ray, and serve the same purpose. 

There are documented cases of tidalems eating the spirits of humans, although rare, due to the remoteness of their natural habitats, and the infrequency with which humans go, with their spirit journeys, to salt water areas.

Trivia

• The bite of an adult tidalem is incredibly powerful, estimated at around 60,000 newtons (6,100 kgf). A similar force has been estimated in the bite of the Tyrannosaurus rex. 
• Tidalem teeth are made of solid mercury, making their bite venomous. 
• Tidalems have extremely slow psychic growth, becoming "sentient" (in the more common use of the word, meaning capable of recognizing themselves as distinct from others, as well as communicating with human-like complexity and intelligence) only after about fifty years. However, their minds are remarkably elastic and never stop evolving; tidalem over a hundred years old are considered extremely wise creatures.