The battle raged on at Kurukshetra on the 14th night of the Mahabharata War.
Jayadratha, the Sindhu King had just been killed by Arjuna at the exact moment before sunset, thereby fulfilling his vow. The soldiers lit torches and continued fighting. Gatotkacha's forces were getting stronger at night and were attacking the Kaurava armies with renewed vigor, forming a Demon-Head formation. Desperate, the Kaurava heroes turned to Karna for aid.
Karna had obtained a celestial weapon from Indra called the 'Shakti', but this could only be used once. He had been saving this weapon to use against Arjuna. But desperate times called for desperate measures.
Taking on the Astra formation, he attacked the Pandava's Demon-Head formation head-on. Karna invoked the celestial weapon and the battlefield filled with radiant light. Without hesitation, he held the weapon aloft and fired it.
The Shakti tore trough the veil of night and streaked towards its target. Gatotkacha watched this unfailing divine weapon coming towards him and realized what was about to pass. Gracefully accepting his fate, he grew to a giant size in an instant. The Shakti crashed into his enormous body, flashing like lightning and echoing through the battlefield like thunder. The mountain then falls over on top of the Kaurava army, crushing thousands of soldiers underneath.
Map of the Battlefield