In Hindu mythology, Arunasura was a demon who had attained the boon from Lord Brahma of not getting killed by any two- or four-legged creatures. Arunasura was killed by Goddess Kali in the form of Bhramari Devi.
In the city of the demons, there lived a powerful demon named Arunasura.
With a view to conquer the Gods, he went to the banks of the Ganges in the Himalayas, practiced a very hard penance, to Brahma, taking him to be the protector of the demons. First influenced by Tamas Guna, he withheld in his body the five Vayus and partook only the dry leaves and repeated, the Gayatri Mantra and practiced austerities. Thus he practiced for full ten thousand years. Then for another ten thousand years the demon lived drinking some drops of water only; then for another ten thousand years he remained by inhaling air only; and then for another ten thousand years he did not take any thing and thus practiced his wonderful penance. Thus practicing his penance, a sort of wonderful halo of light emitted from his body and began to burn the whole world. The demon was practicing his austerities and saw that the demon was immersed in meditation with his eyes closed; and he looked, as it were, blazing with fire, as if a second fire himself. His belly had become dried up, body withered and the nerves of the bodies, too, became almost visible; only the life breath was lingering there.
Later, Arunasura had gotten the boon from Lord Brahma that he will not be killed by any two- or four-legged creatures. Then, puffed up with that boon, the demons Arunasura called on all the other demons that lived in the nether regions. The demons, that were under his shelter, came and saluted him, as their king and, by his command, they sent messengers to the Heavens to fight with the Gods. Hearing from the messenger that the demons were willing to fight with the Gods, Indra trembled with fear and went instantly with the Gods to the abode of Brahma.
Taking Brahma, too, along with them from there, they went to the Vaikunth and took Vishnu with them and all went to Kailash where Lord Shiva lived. There they all held a conference how to kill the demon, the enemy of the Gods.
While, on the other hand, Arunasura, the king of the demon surrounded by his army, went ere long to the Heavens. The demon, then, through the power of his penances, assumed various forms and seized the rights and possessions of the Moon, the Sun, Yamraj, Agni and all the others. All the gods, then, dislodged from their stations went to the region of Kailash and represented to Lord Shiva about their own troubles and dangers respectively. They turned to Parvati, the part incarnate of the Supreme Goddess Kali, to save them to kill Arunasura in the Himalayas, Parvati said that She will because She was aware of Arunasura’s boon that he will be killed by six-legged creatures.
Arunasura’s next intention was to attack Parvati, he has sent in a large, powerful army of his own, She was aware of his boon that She will kill him in the form of a six-legged creature. Devi Parvati then grew to massive size, having four hands holding a mace, trident, longsword and shield. Then from the skies, She closed Her eyes and countless bees, hornets, wasps, flies, termites, mosquitos and spiders came down from the skies like locusts, crawled onto Her body and then clung onto Her like glue and tape, some crawled on Her, bottom to the middle part of Her body, including the back and the front and also some have emanated from her body. Soon, Arunasura and his army saw that Parvati has taken the form of Bhramari Devi.
Arunasura’s army flung their weapons on Her. She blocked their weapons with Her shield and other demons were kicked by it too, She used Her weapons, some were stabbed and decapitated by the long-sword and trident, some were kicked and powdered by the mace. And also some that Bhramari Devi had sent out all bees, hornets, wasps, flies, termites, mosquitoes and spiders to kill them. Now this time, She saw that Arunasura was the last demon remaining in battlefield, She again sent out all of the bees, hornets, wasps, flies, termites, mosquitoes and spiders to kick down Arunasura, they crawled all over him and ripped opened his breasts, chest, back and belly, along with his arms, hands, fingers, legs, feet and toes. Soon after seeing Arunasura’s great fall, the bees, hornets, wasps, flies, termites, mosquitoes and spiders came back to Bhramari Devi and clung on Her again. The gods eulogized the Goddess Bhramari Devi.