An earlier version of Windows (could be 95) would sometimes display an error message when shutting down, to the effect of "The system cannot close, because [...] is still working". In place of [...] you would see the name of the process that was refusing to close. Sometimes though it was as if the system could not even obtain the name of the process, in which case the error message read "...because Unknown is still working".
This is still fairly innocuous in English, but in the Polish version of Windows the message gained a bit of chlling ambiguity. "Unknown" was translated as an adjective in masculine form, which could also be a noun (just like "rich" or "blind" in English), so at first sight you would interpret it as referring to a person. Efectively, the message read "The system cannot close, because the Stranger is still working".
It was a major ROTFL every time.