Is There a Doppelganger in Norse Mythology?

There are all kinds of old pieces of folklore. And just about every country you can explore that has some sort of, and it's usually not good luck if you find your doppelganger. The Varduger is called the Oum-lout with a slash through it. I didn't know that before, did you? Well, you might be a little more of a metal fan than me.