The goblins turned to stone
Then the animal ran away and the terrible dream was over.
This was called a nightmare, or in Dutch a "nacht merrie." "Nacht" means night, and "merrie" a filly or a mare. In the dream, it was not a small or a young horse, but always a big mare that squatted down on a man's stomach.
In those days, instead of seeking for the trouble inside, or asking whether there was any connection between nightmares and too hearty eating of cheese, the Dutch fathers laid it all on the goblins.
The goblins, or sooty elves, that used to live in Holland, were ugly, short fellows, very smart, quick in action and able to travel far in a second. They were first cousins to the kabouters. They had big heads, green eyes and split feet, like cows. They were so ugly, that they were ordered to live under ground and never come out during the day. If they did, they would be turned to stone.
The goblins had a bad reputation for mischief. They liked to have fun with human beings. They would listen to the conversation of people and then mock them by repeating the last word. That is the reason why echoes were called "week klank," or dwarf's talk.
Because these goblins were short, they envied men their greater stature and wanted to grow to the height of human beings. As they were not able of themselves to do this, they often sneaked into a house and snatched a child out of the cradle. In place of the stolen baby, one of their own wizened children was laid. That was the reason why many a poor little baby, that grew puny and thin, was called a "wiseel-kind," or changeling. When the sick baby could not get well, and medicine or care seemed to do no good, the mother thought that the goblins had taken away her own child.
It was only the female goblins that would change themselves into night mares and sit on the body of the dreamer. They usually came in through a hole or a crack; but if that person in the house could plug up the hole, or stop the crack, he could conquer the female goblin, and do what he pleased with her.