Oh, I thought of a tamer example in Polish "ćma" (moth with the death's head on it's back, shadow > "ćiemność")
"Ćmok" which is a word similar to "ćma" can mean something like "ciemno/ciemność/noc/zmierzch". Or "po ćmoku" - "po ciemku" (in the dark). Here it probably means "after dark":
I don't know if it's regional or a countryside thing.
Also, in Slavic mythology "ćmok" was apparently some kind of nocturnal winged demon. Or at least Wikipedia says so:
You can also say "ćmi się" - which means: "it's getting darker".
But again, it's not "literary Polish" (nowadays), I think.