Mahabharata 8.33.63

8.33.63

tasyāḥ paramapāraṃ ca vrajanti vijayaiṣiṇaḥ |
gādhena ca plavantaśca nimajjyonmajjya cāpare || 63 ||

Indeed, as that battle, fraught with carnage of elephants and steeds and men, raged on so fiercely, a river of blood ran from the bodies of (slain) human beings and steeds and elephants. And that current carried away a large number of dead bodies of elephants and steeds and men. Indeed, in that vast host teeming with men, steeds, and elephants, that river formed by the blood of men and steeds and elephants and horsemen and elephant-men, became miry with flesh and exceedingly terrible. And on that current, inspiring the timid with terror, floated the bodies of men and steeds and elephants. Impelled by the desire of victory, some combatants forded it and some remained on the other side. And some plunged into its depths, and some sank in it and some rose above its surface as they swam through it. Smeared all over with blood, their armour and weapons and robes--all became bloody. Some bathed in it and some drank the liquid and some became strengthless, O bull of Bharata's race. Cars and steeds, and men and elephants and weapons and ornaments, and robes and armour, and combatants that were slain or about to be slain, and the Earth, the welkin, the firmament, and all the points of the compass, became red. With the odour, the touch, the taste, and the exceedingly red sight of that blood and its rushing sound, almost all the combatants, O Bharata, became very cheerless.