Oweynagat

That night the three heroes [Laegaire, Conall and Cuchulain] were given as good a feast as before, but they were put to eat it in a room by themselves. When night came on, three enchanted monsters, with the shape of cats, were let out from the cave that was in the hill of the Sidhe at Cruachan, to attack them.

When Conall and Laegaire saw them, they got up into the rafters, leaving their food after them, and there they stayed till morning. Cuchulain did not leave his place, but when one of the monsters came to attack him, he gave a blow of his sword at its head; but the sword slipped off as if from a stone.

Then the monster stayed quiet, and Cuchulain sat there through the night watching it. With the break of day the cats were gone, and Ailell came in and saw what way the heroes were. "Are you not satisfied to give the Championship to Cuchulain, after this?" he said. "We are not," said Conall and Laegaire; "it is not against beasts we are used to fight, but against men."

...


There was at Cruachan the Hill of the Sidhe, or, as some called it, the Cave of Cruachan. It was there Midhir brought Etain one time, and it is there the people of the Sidhe lived; but it is seldom any living person had the power to see them.

It is out of that hill a flock of white birds came one time, and everything they touched in all Ireland withered up, until at last the men of Ulster killed them with their slings. And another time enchanted pigs came out of the hill, and in every place they trod, neither corn nor grass nor leaf would sprout before the end of seven years, and no sort of weapon would wound them. But if they were counted in any place, or if the people so much as tried to count them, they would not stop in that place, but they would go on to another. But however often the people of the country tried to count them, no two people could ever make out the one number.