Llamhigyn Y Dwr [thlamheegin er doorr], or the Water-Leaper was the villain of Welsh fishermen's tales, a kind of water-demon which broke the fishermen's lines, devoured sheep which fell into the rivers, and was in the habit of giving a fearful shriek which startled and unnerved the fisherman so that he could be dragged down into the water to share the fate of the sheep. Rhys, from a second-hand account of it given him by William Jones of Llangollen, learned that this monster was like a gigantic toad with wings and a tail instead of legs (1290: p.270):

'Besides those,' Mr. Jones goes on to say, 'who used to come to my grandfather's house and to his workshop to relate stories, the blacksmith's shop used to be, especially on a rainy day, a capital place for a story, and many a time did I lurk there instead of going to school, in order to hear old William Dafydd, the sawyer, who, peace be to his ashes! drank many a hornful from the Big Quart without ever breaking down, and old Ifan Owen, the fisherman, tearing away for the best at their yarns, sometimes a tissue of lies and sometimes truth. The former was funny, and a great wag, up to all kinds of tricks. He made everybody laugh, whereas the latter would preserve the gravity of a saint, however lying might be the tale which he related. Ifan Owen's best stories were about the Water Spirit, or, as he called it, Llamhigyn y Dwr, "the Water Leaper". He had not himself seen the Llamhigyn, but his father had seen it "hundreds of times." Many an evening it had prevented him from catching a single fish in Llyn Gwynan, and, when the fisherman got on this theme, his eloquence was apt to become highly polysyllabic in its adjectives. Once in particular, when he had been angling for hours towards the close of the day, without catching anything, he found that something took the fly clean off the hook each time he cast it. After moving from one spot to another on the lake, he fished opposite the Benlan Wen, when something gave his line a frightful pull, "and, by the gallows, I gave another pull," the fisherman used to say, "with all the force of my arm: out it came, and up it went off the hook, whilst I turned round to see, as it dashed so against the cliff of Benlan that it blazed like a lightning." He used to add, "If that was not the Llamhigyn, it must have been the very devil himself." That cliff must be two hundred yards at least from the shore. As to his father, he had seen the Water Spirit many times, and he had also been fishing in the Llyn Glâs or Ffynnon Lâs, once upon a time, when he hooked a wonderful and fearful monster: it was not like a fish, but rather resembled a toad, except that it had a tail and wings instead of legs. He pulled it easily enough towards the shore, but, as its head was coming out of the water, it gave a terrible shriek that was enough to split the fisherman's bones to the marrow, and, had there not been a friend standing by, he would have fallen headlong into the lake, and been possibly dragged like a sheep into the depth; for there is a tradition that if a sheep got into the Llyn Glâs, it could not be got out again, as something would at once drag it to the bottom. This used to be the belief of the shepherds of Cwm Dyli, within my memory, and they acted on it in never letting their dogs go after the sheep in the neighbourhood of this lake. These two funny fellows, William Dafydd and Ifan Owen, died long ago, without leaving any of their descendants blessed with as much as the faintest gossamer thread of the story-teller's mantle. The former, if he had been still living, would now be no less than 129 years of age, and the latter about 120' (635: Vol.I, p.78-80).