Mbh 7.178.1a

“Sanjaya said, ‘Seeing Bhima in that battle assailed by the cannibal, Vasudeva, approaching Ghatotkacha, said unto him these words, “Behold, O mighty-armed one, Bhima is violently assailed by the Rakshasa in battle, in the very sight of all the troops and of thyself, O thou of great splendour! Abandoning Karna for the present, quickly slay Alayudha, O mighty armed one! Thou can afterwards slay Karna.” Hearing these words of him of Vrishni’s race, the valiant Ghatotkacha, abandoning Karna, encountered Alayudha, that prince of cannibals and brother of Vaka. The battle then that took place at night between those two cannibals, viz., Alayudha and the son of Hidimva became fierce and dreadful, O Bharata. Meanwhile, the mighty car-warrior Yuyudhana, and Nakula, and Sahadeva, pierced with keen shafts the warriors of Alayudha, those terrible-looking and heroic Rakshasas, armed with bows. The diadem-decked Vibhatsu, O king, in that battle, shooting his arrows on all sides, began to overthrow many foremost of Kshatriyas. Meanwhile, Karna, O king, in that battle agitated many kings and many mighty car-warriors amongst the Panchalas headed by Dhrishtadyumna and Sikhandin and others. Beholding them slaughtered (by Karna), Bhima, of terrible prowess, rushed speedily towards Karna, shooting his shafts in that battle. Then those warriors also, viz., Nakula and Sahadeva and the mighty car-warrior, Satyaki, having slain the Rakshasas, proceeded to that place where the Suta’s son was. All of them, then, began to fight with Karna, while the Panchalas encountered Drona. Then Alayudha, excited with rage, struck Ghatotkacha, that chastiser of foes, on the head, with a gigantic Parigha. With the stroke of that Parigha, the mighty son of Bhimasena, endued with great prowess, seemed to be in a state of partial swoon and sat down motionless.