It was such an odd trout that Nona hauled in at the end of his fishing-line. Large and fat, red spotted and shiny, it sprawled and squirmed, with its dirty yellow belly above the water, to wriggle off the hook. And when he got it into the boat, and took it off the hook, he saw that it had only two small slits where the eyes should have been.
It must be a huldrefish, thought one of the boatmen, for rumour had it that that lake was one of those which had a double bottom.
But Nona didn't trouble his head very much about what sort of a fish it was, so long as it was a big one. He was ravenously hungry, and bawled to them to row as rapidly as possible ashore so as to get it cooked.
He had been sitting the whole afternoon with empty lines out in the mountain lake there; but as for the trout, it was only an hour ago since it had been steering its way through the water with its rudder of a tail, and allowed itself to be fooled by a hook, and already it lay cooked red there on the dish.
But now Nona recollected about the strange eyes, and felt for them, and pricked away at its head with his fork. There was nothing but slits outside, and yet there was a sort of hard eyeball inside. The head was strangely shaped, and looked very peculiar in many respects.
He was vexed that he had not examined it more closely before it was cooked; it was not so easy now to make out what it really was. It had tasted first-rate, however, and that was something.
But at night there was, as it were, a gleam of bright water before his eyes, and he lay half asleep, thinking of the odd fish he had pulled up.
He was in his boat again, he thought, and it seemed to him as if his hands felt the fish wriggling and sprawling for its life, and shooting its snout backwards and forwards to get off the hook.
All at once it grew so heavy and strong that it drew the boat after it by the line.
It went along at a frightful speed, while the lake gradually diminished, as it were, and dried up.
There was an irresistible sucking of the water in the direction the fish went, which was towards a hole at the bottom of the lake like a funnel, and right into this hole went the boat.
It glided for a long time in a sort of twilight along a subterranean river, which dashed and splashed about him. The air that met him was, at first, chilly and cellar-like; gradually, however, it grew milder and milder, and warmer and warmer.
The stream now flowed along calmly and quietly, and broadened out continually till it fell into a large lake.
Beyond the borders of this lake, but only half visible in the gloom, stretched swamps and morasses, where he heard sounds as of huge beasts wading and trampling. Serpent like they rose and writhed with a crashing and splashing and snorting amidst the tepid mud and mire.
By the phosphorescent gleams he saw various fishes close to his boat, but all of them lacked eyes.
And he caught glimpses of the outlines of gigantic sea-serpents stretching far away into the darkness. He now understood that it was from down here that they pop up their heads off the coast in the dog days when the sea is warm.
The lindworm, with its flat head and duck's beak, darted after fish, and crept up to the surface of the earth through the slimy ways of mire and marsh.
Through the warm and choking gloom there came, from time to time, a cooling chilling blast from the cold curves and winds of the slimy and slippery greenish lichworm, which bores its way through the earth and eats away the coffins that are rotting in the churchyards.
Horrible shapeless monsters, with streaming manes, such as are said to sometimes appear in mountain tarns, writhed and wallowed and seized their prey in the fens and marshes.
And he caught glimpses of all sorts of humanlike creatures, such as fishermen and sailors meet and marvel at on the sea, and landsmen see outside the elfin mounds.
And, besides, that there was a soft whizzing and an endless hovering and swarming of beings, whose shapes were nevertheless invisible to the eye of man.
Then the boat glided into miry pulpy water, where her course tended downwards, and where the earth-vault above darkened as it sank lower and lower.
All at once a blinding strip of light shot down from a bright blue slit high, high, above him.
A stuffy vapour stood round about him. The water was as yellow and turbid as that which comes out of steam boilers.
And he called to mind the peculiar tepid undrinkable water which bubbles up by the side of artesian wells. It was quite hot. Up there they were boring down to a world of warm watercourses and liquid strata beneath the earth's crust.
Heat as from an oven rose up from the huge abysses and dizzying clefts, whilst mighty steaming waterfalls roared and shook the ground.
All at once he felt as if his body were breaking loose, freeing itself, and rising in the air. He had a feeling of infinite lightness, of a wondrous capability for floating in higher atmospheres and recovering equilibrium.
And, before he knew how it was, he found himself up on the earth again.
 Hulder, huldre, a name for anything elfin or gnomish. Compare Icel. Hulda, a hiding, covering. It implies the invisibility of the elfin race.
 Ligorm, serpent that eats the dead. If we have Lichfield and lichgate, we may have lichworm too.