The bowstring and the ants: how Vishnu lost his head
Vishnu wins the gods' contest at Kurukshetra, cannot master his love of glory and stands leaning on his bow. Ants gnaw the string for a reward, the bow springs apart and cuts off his head, which becomes the sun. The Devi Bhagavata retells the accident and replaces the head with a horse's.
Agni, Indra, Soma, Makha, Vishnu and all the gods except the Ashvins sit in sacrifice at Kurukshetra, agreeing that the first to reach its end shall be the best and that the gain be common. Vishnu reaches it first but cannot control his love of glory. He steps aside with bow and three arrows and stands with his head on the bow's end while the gods sit round him. The ants ask what they would get for gnawing the string and are promised food and water even in the desert. They gnaw; the bow springs apart and cuts off his head, which falls with the sound ghrin and becomes the sun. Indra reaches the body first and takes its glory, so he is called Makhavat. The gods divide the headless sacrifice into the three pressings. The rite called Pravargya is explained from this.
The gods sacrifice for glory with Kurukshetra as their altar. Glory comes to Makha Vaishnava, who leaves with it; a bow grows from his left hand and arrows from his right, and the many cannot overcome the one. He smiles at this, and as he smiles his strength leaves him and becomes the shyamaka grain. The ants first ask a boon, to find water wherever they dig, then gnaw the string. The bow hurls his head upward and it travels through heaven and earth. The gods divide him in three but gain nothing from a headless sacrifice. They ask the Ashvins, the physicians, who put the head back in return for a Soma cup, and then the gods win heaven.
What is different here:
The victim is Makha Vaishnava; adds the bow born from his hands, the smile, the grain, the ants' own boon, and the Ashvins restoring the head. Read in Muir's text and translation.
Agni, Indra, Vayu and Makha sacrifice for glory and agree to share it. Glory comes to Makha, who takes it and leaves. The others surround him. He stands leaning on his bow, and the end of the bow springs up and cuts off his head. He becomes the Pravargya; Makha is the sacrifice, and those who perform the Pravargya put the head of the sacrifice back.
What is different here:
No Vishnu by name, no ants and no sun; the bow end springs up by itself.
Worn out by ten thousand years of battle, Vishnu falls asleep sitting with his head on the end of his strung bow. The gods need him for a sacrifice. Indra asks how to wake him; Shiva fears his anger; Brahma creates a white ant to eat the bow end. The ant objects that waking a sleeper is a sin and is promised the ghee that falls outside the fire pit. It gnaws, the bow springs with a terrible noise, and Vishnu's head vanishes. The gods weep and pray to the Goddess. Her voice explains two causes: Lakshmi, thinking Vishnu laughed at her face, had cursed his head to fall; and a Daitya named Hayagriva can be killed only by one who is horse-faced. Vishvakarma fixes a horse's head on Vishnu, who as Hayagriva kills the Daitya.
What is different here:
Sleep instead of pride; the gods mean only to wake him; a curse by Lakshmi and the Goddess's plan lie behind it; the head is lost in the ocean, not turned into the sun, and is replaced by a horse's head.
Sources: The Satapatha-Brahmana, tr. Julius Eggeling (Sacred Books of the East 12, 41); Original Sanskrit Texts, vol. 1 (2nd ed.), J. Muir; The Srimad Devi Bhagawatam, tr. Swami Vijnanananda (1921-22), Book 1 chapter 5