Satyaki had some inkling of such misadventure by Duryodhana. Satyaki told Krishna about the plan of Duryodhana. He said to Dhritarastra, "My lord, see the lunacy of your son Duryodhana. He is planning to capture Krishna. He is trying to hold the sun in his hands." Vidura started lamenting for the son of the king. He became very sad thinking about the great misfortune coming to the king in his old age.
Krishna smiled at him and said, "Please do not grieve for me. It is not very easy to capture me." Then he addressed Dhritarastra, "My lord your son has committed all sorts of sinful acts, now this is the last of his sinful acts." Dhritarastra was alarmed. He called for Duryodhana. He said to Duryodhana, "Steeped in sin as you are, I could never imagine that you would stoop so low. What is this lunacy? You are dreaming of capturing the greatest man on earth. Neither the gods nor the rishis are powerfull enough to do this you can take the sun in your hands more easily." Krishna said to Duryodhana," You want to capture me, look. Speaking this Krishna laughed and his body was emblazoned with a divine light.
All the gods were seen coming out of his body. They looked very small in comparison to the universal form of Krishna. Brahma was on his forehead. Eleven rudras were on his chest. Indra, Varuna, Kubera and Yama were seen on his shoulders. Agni was coming out of his mouth and the nostrils. Twelve Adityas, eight Vasus, all maruta and gods were seen in his body. The Pandavas, Balarama all Vrishni warriors, all Andhakas were seen with their weapons.
Krishna was seen as having, innumerable hands, all kinds of weapons were there. His conch Panchajanya was there. His Sudarshana Chakra was there, in one hand he was wielding his mace Kaumudiki. He eyes and nostrils were throwing out great flames. This aspect of his form was very terrible. It was as if the death was there in the person of Krishna. His divine splendor and glitter dazed everyone. No one was able to look at him except Bhishma, Drona and Vidura and some of the great sages present there. They were unable to satisfy their thirst for this vision. They were desirous of seeing it forever. Krishna granted divine vision to Dhritarastra so he could also witness this divine spectacle. Looking at this divine form again and again overwhelmed him.
Divine music was heard and the rain of flowers continued through out. Dhritarastra's eyes were shedding stream of tears. He prayed with folded hands that he was completely satisfied by having the vision of the lord. He no longer want to see anything else. He prayed that his eyes be taken back. Lord accepted his prayer. Dhritarastra became blind again.
Krishna came back to his normal self. He took the hands of Vidura and Satyaki and went out of the assembly hall. He took leave of all the sages present there. The sages left after Krishna. The kings who were there came after chariot and army at the gate of the palace. Krishna went to Vidura's house without looking at the kings present there. His eyes were very sad. At Vidura's house he touched feet of Kunti and told her about the happenings in the assembly hall. He said that the Pandavas shall regain their lost glory soon. They shall get back their kingdom and the darkness will clear. Kunti asked Krishna to convey her blessings to all her sons and daughter in law Draupadi. She started crying recalling the hardships suffered by the Pandavas during their thirteen-year exile. Krishna started for Upalavya after taking leave of Kunti.
Duryodhana roared, after Krishna left, that the war should start at the earliest. The eleven "akshauhims of army marched towards the field called "Kurukshetra". Dhritarastra, Drona, Bhishma, Kripa tried to see him reason once again but he was beyond all advice. Victory or death in the battle was the only thought in his mind.
http://www.urday.in/mvishwaroop.htm