Ilvala
Ilvala () and Vatapi were rakshasas and brothers. Legend has it that both were vanquished by the sage Agastya. Rakshasa. They ruled from Badami, formerly known as Vatapi, named after rakshasa king Vatapi. According to the Mahābhārata, Vatapi ruled the area along with Ilvala. Once Ilvala hosted a tapasvi Brahmin with reverence and asked him to grant a boon. He desired to have a son equal to Indra. But the sage did not oblige. Following this, his anger turned to hatred against all Brahmins and mendicants. Ilvala and Vatapi took a grudge against all sages. Vatapi knew the art of  transformation and had the power to change into any life form. Ilvala knew the ‘Mritasanjivani’ mantra to bring back the dead. They used these powers to loot and kill. Ilvala invite a brahman to a feast and Vatapi would turn himself into a Goat. The Bhagavata Purana mentions that Ilvala had a son named Balvala, who used to disturbed the sages present at Naimisha forest when the sages heard the narration of various Puranas from Sauti. Later, Balarama during his pilgrimage kills him. Encounter with Agastya. Ivala invited the sage Agastya and received him with reverence and honour. Sage Agastya , with his divine power, knew the intention of the hosts and wanted to end their transgressions. Agastya ate the food served to him. As soon as the sage finished eating, Ilvala called,"Vatapi atragacha" (Vatapi come here). Immediately, Agastya passed his right hand over his stomach and said,"Vatapi Jeernobhava" (Vatapi got digested). Vatapi could not come out of Agastya's stomach and that was the end of the demon. Ilvala, was scared. He went on shouting "Vatapi atragacha" Agastya then said, "Oh, you wicked Ilvala, you wanted to kill me, but your brother Vatapi cannot come out! He is already  digested". Ilvala decided to take revenge on Agastya for killing his brother and attacked Agastya. With the power of his "tapas" (penance), Agastya reduced Ilvala to ashes. This happened in the southernmost state of Tamil Nadu place where known as Konnur (where Vatapi and ILvala) got killed by sage Agastya . And the present day name changed to Villivakkam in chennai. And the burnt place is Kolathur in chennai. Both places has shiva temple installed by Agastya. In Villivakkam Sage Agastya has build lord shiva temple to forgo his pabha and started his tapas towards lord shiva. And after his long  tapas lord Shiva appeared in before him on the month of Aadi in Tamil, Aashada in Sanskrit on the first tuesday, After that he received lord shiva blessings and his all sins were removed, And this place is one of the important and oldest shiva temple in chennai. People from several places do visit Arulmigu Sri Agatheeswarar Temple in villivakkam during month of Aadi/Aashada.