Tarrasque

We do not intervene, for only in the face of pure terror, can the beauty of true courage be revealed. Only in the face of this mighty challenge, can a Paladin such as yourself, last of your party, rise up and show your worth. Only in the wake of total destruction can a nation as corrupt as this be created anew. - Lathander, God of Birth and Renewal, when asked in desperation why the gods will not intervene to protect a city and its people from destruction by the Tarrasque.

Introduction
Few have seen one, and of those that have fewer still have survived to tell the tale. The Legendary Tarrasque is is embedded deeply in the minds of the peoples of the Material Plane as an agent of destruction. Its power goes far beyond the mere destruction it is physically capable of, it becomes an object to be feared or even worshiped. The Tarrasque is nothing less than a force of nature.

Physiological observations
...Well it's not like you can sit either yourself or the beast down long enough to paint its portrait. Most sensible people would be running like mad in the other direction  - Spokesperson of the Monster Hunters Association of Adventurers, when asked why there are so many differing descriptions of Tarrasque physiology.

Legends state that the Tarrasque was created by the Primordials in combination with the Princes of Elemental Evil as a weapon against the gods, some of which sacrificed their lives to ensure the creation was a success. Its physiology certainly bears witness to this creation, being more biological machine than animal.

A Tarrasque is typically seen to be around 50 feet tall and 70 feet long including the tail. Universally accounts of the creature have mentioned the two, forward protruding horns and large clawed hands.

Tarrasques have been observed to have three stomachs. The first, containing constricting muscles and sharp internal bony protrusions ensures that any living matter is deceased before it continues through the digestive tract. The second stomach applies acid to further break down the Tarrasque's meal and strip magic from the swallowed. Finally, the third stomach is a furnace ensuring that the swallowed item is entirely vaporized into its component parts and absorbed into the body of the tarrasque.

One bio-engineering problem that the creators of the Tarrasque encountered, was that of blood-flow. Animals with appendages a great distance from their heart can have issues of of circulation and blood pressure. For example, when a humanoid, having been lying down for a period will experience momentary dizziness if they suddenly stand up. Conversely if they lower their head below their heart for a long period, blood will pool in its head with nothing to draw it out except the vacuum created by the heart pushing blood in the opposite direction. This effect is exacerbated in larger creatures, necessitating larger hearts.

At the end of the day, after all the running, screaming and destruction has stopped, a Tarrasque is really all heart  - Anonymous Biologist

The beings that engineered the Tarrasque have solved this problem, and granted additional advantages by ensuring that veins and arteries are walled with thin muscle tissue.

These unique veins can ensure that blood reaches the Tarrasque's head in sufficient quantities when it is standing, and prevent over-pressure in the head when the Tarrasque bends down to bite at a tasty humanoid or beast. An advantageous side effect of this, is that any wounds that a Tarrasque sustains can be more efficiently closed off and prevented from bleeding, without having to entirely rely on blood platelets. Thus, it is nearly impossible for a Tarrasque to bleed out.

A Tarrasque has two brains. One in the head, which controls movement and processes sensory input, and one at the base of the spine near the hips. This secondary brain, buried deep under the thick rear hide assists in controlling reflexes for the lower half of Tarrasque's body and contains critical brain matter such as the oversize pituitary gland which regulates blood pressure, vein/artery constriction and growth hormones. It is imagined that this could be the source of the Tarrasque's fabled regeneration capabilities.

Social Observations
The Tarrasque has never been observed in groups of more than one. It could be said that they are inherently anti-social creatures, obeying their primal urge to destroy.

Behavioural Observations
Tarrasques know nothing except the urge for destruction. Once awakened, they emerge from the earth and lumber towards the nearest settlement, whether on the surface, or in the underdark, Tarrasque's do not discriminate.

When encountering a particularly troublesome foe, the Tarrasque will focus its attention until the pest is eliminated. In this, the Tarrasque displays unexpected swiftness of movement and surprising tactical ability given its low intelligence. utilizing all the weapons at its disposal, swiping its claws and swinging its tail as the situation demands.

Tarrasques have been observed to move through solid rock or "earthglide" on occasion. This has certainly been the case with Tarrasque corpses in the past. On their demise, the body remains for up to 2 days, before melting into the earth to regenerate.

Intra-species Observations
It has often been noted by those of stronger minds that the stampede to escape the path of a raging Tarrasque kills more people than the Tarrasque itself.

Variant Species
From the few reliable sources that we have describing the physical appearance of the Tarrasque, we can deduce that either there are multiple species, or that the Tarrasque takes on the appearance of the terrain from which it emerges. Should it awaken and emerge through a forest, it may contain the limbs of great trees sprouting from its carapace and limbs. Reports of its diamond hard shell may have been written by those who observed a Tarrasque which regenerated and emerged from its slumber near a gem mine.

Should this hypothesis prove true, one can only imagine the horror of a Tarrasque awakened from inside a volcano.