The being I'm talking about, in Danish called 'nissen', is a small man-like creature or spirit.
In the old folklore they helped owners and servants (mostly the latter) of farms...
If they threated him treated him well, that is!
Especially around Christmastime the humans living there had to serve him a big bowl of rise pudding* with cinnamon and butter on top.
If he was angered by not getting this (or being cheated in another way, like if the butter was hidden under the pudding) he would take revenge. That could, for an example, be by killing a good cow or other such thing.
Nowadays they have been reduced to a mischievous Christmas-spirit that, in our tellings, serves the same role as elfs do in yours.
There is quite a lot of problems with name translation, as there often is. There simply is no single word for our 'nisse' in english. But I beliave we can use the Danish word then, right? I did my best to describe them.
*Rise pudding was the best translation I could give.
And a note: the black stripes on his hat is a personal touch.