Doestheblackmoonhowl is a common code word in SCP Foundation, a story of a mysterious system on the internet First appeared in SCP-256. In SCP worldview, the meaning of "whether the dark moon howls" is like a secret code, which can be used in many second sentences. In different articles, there will be different second sentences as correct answers, otherwise it will be regarded as a password error. Another common setting is that different answering passwords symbolize the security level, identity and intention of the answering personnel, so as to illustrate that different and identical answers appear in the text. Now there are also some secret codes to respond, such as: only when the moon is lost. The dog of hell has three heads. Black Moon sings in memory of the forgotten war victims. When all is silent.