Source: Into the Darklands, pg(s). 56
Seugathi are a subterranean race of intelligent, tentacled worms that served even more bizarre, alien masters in the darkest depths of the earth. These monstrous creatures follow strange orders that often seem completely insane to humans.
Seugathi resemble a horrible cross between an enormous caterpillar and a writhing worm, its body stretching to about fourteen feet in length. It tends to rear up on the rear half of its body using its dexterous caterpillar like legs to support itself. The head sit directly at the top end of the body and is covered in horrible, insect-like emerald eyes below which sits its alien mouth, a vortex of teeth from which three sharp, bony jaws that click and clack menacingly. At the other end of the body its torso splits into two long, slender tentacles. These tentacles are each about six foot in length and are incredibly dexterous, able to perform delicate manipulations as easily as if they had human hands. In combat Seugathi often wield additional weapons in their tentacles making them even more fearsome opponents.
Habitat & Ecology
Seugathi dwell or at least begin their lives in the deepest depths of the Darklands in the orvian vault of Denebrum for it is the home of their dark masters. Denebrum is the land of the neothelids, huge worms with incredible mental powers who are the creators of the seugathi who serve them as fanatically loyal servants. They are created when a neothelid spawns hundred of young seugathi into a pit like depression, they are only a foot long when spawned but grow quickly, consuming their brothers and sisters. Within a year only one fully grown seugathi remains. Having consumed the flesh and the minds of its fellows the new born seugathi is filled with numerous missions as each juvenile seugathi is created with a single purpose. These missions often seem insane but normally further their secret purpose which often involve the summoning of creatures from the dark tapestry, creatures like the Havero or the spawn of Yog-Sothoth.
Apart from their birth the other most aberrant aspect of the seugathi is their feeding habits, while they can survive off of underground fungus or the flesh of subterranean creatures their favoured food is the rational thoughts of sane beings. These thoughts give them some sort of bizarre sustenance, unfortunately in eating their thoughts the seugathi completely destroys the sanity of the creature, at first leaving them confused and bewildered but by the end the victim is a gibbering, insane mess. Seugathi can repress this hunger and don't have to feed constantly but only do so in the most important of circumstances and when denied their favourite food seugathi become even more short tempered and violent. Another interesting facet of their ecology is that their bite is poisonous and the poison actually makes their victims more susceptible to their feeding.
Seugathi are generally loners and rarely deal well with other creatures though they can sometimes be found in small groups of their own kind referred to as cults. Sometimes their strange missions require seugathi to become a part of non-seugathi societies, often other darkland civilisations like the drow or the equally mad derro. When interacting with others they cant take on a variety of roles from religious leader, to profane advisor to simple guardians or servants. When forced to become a part of these societies the seugathi must exercise extreme self control in their thirst for sane thoughts otherwise they are sure to be destroyed for their sanity draining abilities.