Ashwatthama returned to Duryodhana, proudly carrying the bag of five heads.
"I killed the Pandavas!" he said.
"Show me," Duryodhana said in disbelief. "Give me Bhima's head."
Ashwatthama gave him a head, and Duryodhana took it and crushed it between his fingers.
"No!" said Duryodhana. "This is not Bhima; I would not be able to crush his head so easily. Who have you killed?"
Then Ashwatthama realized: he had killed the five sons of Draupadi. These were not the Pandavas.
"I have lost the war," Duryodhana sighed, "but the Pandavas... they too lost everything."
And with those words, he died.
Inspired by: Jaya: An Illustrated Retelling of the Mahabharata by Devdutt Pattanaik.
Notes: This story is on p. 293. Kripa went on to survive the war and even became the teacher of Parikshit, the last scion of the Pandavas; more at Wikipedia: Kripa. Kritavarma later died in the slaughter of the Yadavas; more at Wikipedia: Mausala Parva.