a false alarm
In Jin Dynasty there was a man named Yue Guang who was fond of drinking alcohol.
He got so much frightened that he took ill in bed after getting home.
Yue Guang came to see him and asked about the cause of his disease.
When he got to know the cause, he pulled his friend from the bed immediately and took him to his house.
Yue Guang made his friend sit where he used to, pouring a goblet of alcohol for him, and asked him," Is there any snake reflection in the goblet?"
There was still a "snake reflection" in the goblet! Yue casually took away the bow hanging on the wall.
This time, the "snake reflection" disappeared.