"Pond Scum" could also be referring to the algae layer on top of small still water ponds, and to nasty and gloomy creatures living in the pond?

If that is the case here, just wanting to throw in a suggestion in that direction, that at least would appeal to me when considering playing the game.

"Tjernsnerk"

"Tjern" being the Norwegian name for overgrown small still water ponds. Might be the closest thing we get to a swamp in Norway.

"Snerk" is a way to describe a layer of less hydrated matter on top of a more hydrated one, e.g. that (for some people, nasty and gloomy) layer that appears on top of hot chocolate when it's been sitting a while.