Here's another mushroom (Pilz), but this one is less endearing than the Glückspilz we dealt with in the past. Spalten means "to split" or, if you are in the mood, "to rend asunder". Spaltpilz used to be a botanical term for a bacterium, which, after all, multiplies by splitting. In biology, this term has been replaced by Bakterie in German, but Spaltpilz remains very much in the language in a metaphorical meaning, to denote someone who works hard to split a group into factions.
[Source: Wild Things in the German Language: Kindle version | iBooks version]