The Tcha'besheh (or Underlier), referred to as the A'kweth (the hidden), was a large silicon-based life form that lived on Vulcan.
- No more than glimpses have ever been seen of them, through all the many centuries: a huge, broad, glittering back—but is it a back?—crusted with sand, the size of a great house; or a tentacle or two, playing with a bright stone, vanishing when surprised. (TOS novel: Spock's World)
History and specifics[]
Biology[]
Very little is known about the creatures' biology or their evolution. They do not apparently need to respire, require oxygen or feed and were one of the first recorded species that lived on a planet alongside a carbon-based lifeform - namely, the Vulcans. (This would change somewhat upon the discovery of the Hortas of Janus VI.) They were large beasts that were the size of a great house and possessed several tentacles.
Some have compared the creatures to the dinosaurs of the planet Earth, however unlike the large reptiles of the Human home world, the Tcha'besheh never went extinct and continued a secluded life far beneath Vulcan's surface. Scans were difficult if not impossible to get from the creatures as the natural elements between the equipment would prevent an individual from getting many readings. What has been learned from such scans include a life-sign reading suggesting a level of vitality equal to a thousand creatures, which makes pinpointing an Underlier very difficult.
- Sensors turn up vast life-sign readings, a level of vitality and power that would normally belong to a thousand creatures: but movement readings rarely pinpoint more than one source of motion, sliding leisurely through the deep sand of the greater deserts, skirting the outcroppings of mountains as a cruising whale might skirt islands or shoals. Sometimes a tracked vital sign disappears completely, without explanation, without trace. (TOS novel: Spock's World)
They are considered to be the Vulcan equivalent of whales that travel beneath the sands of their home world.
Some scientists think they may have been seeded on Vulcan by the Preservers
Myth and legend[]
Ancient Vulcan mythology considered the Underliers repository of all knowledge.
It is said they are telepathic and have made mind-to-mind contact with Vulcans, often at important and pivotal moments in Vulcan's history.
- ...and it roared a long singing roar like the wind in the trees during a hard rain. The flood of images that blasted through the wanderer made him clutch his head, so strange they were; lives and deaths were in them, and terrible heat and pressure, and odd desires and triumphs, but above all darkness, a sweet, enclosing, down-pressing darkness that made this mere night look like white day by comparison—a barren, exposed, inhospitable thing. (TOS novel: Spock's World)
Some modern Vulcans still sometimes believed they had a mystical encounter with A'kweth. (TTN novel: The Red King)
Language[]
In the ancient days when the proto-Vulcans had developed rudimentary tribes, but not language, the proto-Vulcan known as The Wanderer learned his first word (heya, meaning mountain) through an encounter with an Underlier. This was shortly before an intense solar flare from 40 Eri transformed Vulcan into a desert world.
Vulcans' racial memory and history hold that the word for mountain has not changed in the entire history of their people. (TOS novel: Spock's World)
Surak[]
Surak is said to have had an encounter with an Underlier when he sojourned into the desert before he began teaching logic and emotional control that may or may not have had a significant influence on his choice to try to change and reform his world and culture.
- The quake got worse. Surak became uneasy and started to scramble to his feet. And subsided, as the earthquake rose up before him. With frightened calm he watched the sand vibrate, heard it drum like a hundred ancient war-parties all around him. Well, he thought, as the bulge came up and up, I chose, and I suppose that was enough. And now I die—The sand started to slip away from the great shape it covered, as the Underlier arched its back against the night, huge as a house, as a hundred houses. It blotted out Seleya, it blotted out T’Khut, and the sky. The low rumbling of its voice would have blotted out a real earthquake, had one had the temerity to take place right then. Terror was a poor word for what possessed Surak in that moment. His tongue clove to the roof of his mouth, and he shook all over. He had not thought that his death could be so big—that anything could be so big. And then his death spoke to him . . . and he found that he was mistaken about it being his death. The song was of incredible complexity and depth—the kind of melody you might expect a mountain, or perhaps a geological stratum, to sing. The thoughts that came with the song, that blasted into his head and crashed through him like a continent collapsing on him, were immense, wide, old—and so strange that he could not even begin to say what they were about. But he got a clear sense that this immensity, this ultimate power, was looking at his smallness, his delicacy, his tiny precision, with astonishment. And with delight at his difference. (TOS novel: Spock's World)