"Muggen sopp i skogen" are moldy mushrooms in the wild.
The Henrik hates the "muggen sopp i skogen", and whenever he sees one while he's on the tur in the skogen, he goes into a temper tantrum and gets a heart attack afterwards, nobody knows why.
Person: Hey Henrik, i think i see a muggen sopp over there, in the skogen.
Henrik: LASJHKØGYAJHKSLØDFYUGASBHJKFGHAVJSDKPDH NEIIIIIII JEG SKAL BANKE DEG ASKODJIUHASJID, FUCK MUGGEN SOPP I SKOGEN!!
2) A human who accidentally got into santa's bag, and was raised by elves, who because of his human form, cannot make toys as fast as the elves and is inferior.
Buddy: "Why don't you just say it? I'm the worst toy-maker in the world. I'm a Cotton Headed Ninny Muggins."
Elf: "No Buddy, you're not a Cotton Headed Ninny Muggins. We all just have different talents, that's all."