Fin MacCumhail and the Son of the King of Alba
When he came to the lake, the man started to plough, drew one furrow. The lake began to boil up, and as he was coming back, making the second furrow, the serpent was on the field before him and swallowed the seven bullocks and the plough up to the handles. But the man held fast to what he had in his two hands, gave a pull, and dragged the plough and six of the bullocks out of the belly of the serpent. The seventh one remained inside. The serpent went at him and they fought for seven days and nights. At the end of that time the serpent was as tame as a cat, and the man drove him and the six bullocks home before him.
When he was in sight of Fin's castle, the sentry at the gate ran in and cried: "That cowherd is coming with the size of a mountain before him!" "Run out," said Conán Maol, "and tell him to tie the serpent to that oak out there."
They ran out, and the man tied the serpent to the oak-tree, then came in and had a good supper.
Next morning the man went out to herd cows as before. "Well," said Conán Maol to Fin, "if you don't put this man to death, he'll destroy you and me and all the Fenians of Erin."
"How could I put such a man to death?"
"There is," said Conán, "a bullock in the north of Erin, and he drives fog out of himself for seven days and then he draws it in for seven other days. To-morrow is the last day for drawing it in. If any one man comes near, he'll swallow him alive."
When the cowherd came to supper in the evening, Fin said to him: "I am going to have a feast and need fresh beef. Now there is a bullock in that same valley by the lake in the north of Erin where you punished the serpent; and if you go there and bring the bullock to me, you'll have my thanks."
"I'll go," said the man, "the first thing after breakfast in the morning."
So off he went next morning; and when he came near the valley, he found the bullock asleep and drawing in the last of the fog; and soon he found himself going in with it. So he caught hold of a great oak-tree for safety.