about a sentence

Sometimes, country people in the United States will refer to "a bad moon," meaning that people are aggressive and angry, and that there will be trouble in their area. It is an outdated expression, however, and was never very commonly used.

I should note that the origin of the expression is a popular folk belief (for which no reliable evidence has ever been produced) that the full moon causes people to act more outrageously.

a song
credence clearwater revival

I see the bad moon arising.
I see trouble on the way.
I see earthquakes and lightnin.
I see bad times today.

Chorus:
Dont go around tonight,
Well, its bound to take your life,
Theres a bad moon on the rise.

haha, I think I'v got it. It's more like a chinese word "Yu Men",which is commonly used by youth.

Thank u Setanta,dadpad