Daniel 5:6

‘Then the king's face was changed on him, and his thoughts upset him greatly, and the joints of his limbs went slack and his knees smote one against another.'

The effect on the king was dramatic. He was absolutely terrified. The picture is of someone in a blue funk. This serves to confirm that his attitude was one of deliberate blasphemy, for he now recognised that the God Whom he had been blaspheming was here to deal with him.