From Scandinavian Folklore, William Craigie, 1896
The River Horse
The river-horse (bäck-hästen) is very malicious, for not content with leading folk astray and then laughing at them, when he has landed them in thickets and bogs, he, being Necken himself, alters his shape now to one thing and now to another, although he commonly appears as a light-grey horse.
It is certain that the river-horse still exists, for it is no more than a few years back that a man in Fiborna district, who owned a light-grey horse, was coming home late one night and saw, as he thought, the horse standing beside Väla brook. He thought it strange that his man had not taken in Grey-coat, and proceeded to do so himself, but just as he was about to lay hold of it it went off like an arrow and laughed loudly. The man turned his coat so as not to go astray, for he knew now who the horse was.
In Kristianstad there was a well, from which all the girls took drinking water, and where a number of the boys always gathered as well. One evening the river-horse was standing there, and the boys, thinking it was just an old horse, seated themselves on its back, one after the other, till there was a whole row of them, but the smallest one hung on by the horse’s tail. When he saw how long it was he cried, “Oh, in Jesus’ name!” whereupon the horse threw all the others into the water.
One evening, many years ago, some young girls from Ryslinge had been out at a farm in Skirret, to help the woman there to card her wool, and it was pretty late before they started home. They followed the path from Skirret to Ryslinge, which went through the marsh. The girls were frightened as to how they were to get over this dangerous spot, but on coming to it they found there a lean old horse, so lean that one could count its ribs. The boldest of the girls immediately mounted on its back, and the others followed her example, for the more that mounted it, the longer grew the horse. They then rode into the marsh, but when they had got half way over, the foremost girl looked behind her, and when she saw that they were all on one and the same horse, she was so scared that she cried out,
“Jesus Christ’s cross!
We are sitting all on one horse.”
As soon as this was said, the horse suddenly disappeared, and the girls were left standing in the middle of the bog, and had to wade to land.