Vadavagni is a form of Agni (fire) that is mentioned in the Hindu scriptures. It is believed that it is the escape of this fire from under the ocean which will finally consume the current cycle of creation and prepare the universe for the next cycle of creation.
Hindu Puranas states that Vadavagni was born in the lineage of Sage Bhrigu. The sons of Kartavirya Arjuna in order to finish off the lineage of the Sage Bhrigu started killing descendents of Bhrigu including children. A wise woman of the lineage, who was pregnant, in order to save her child moved the unborn child from her womb to her thighs. When the child was born it was called Aurva.
Later when the sons of Kartavirya came to know about the child they came to kill it. When they held it up they became blind due to the rays that emitted from the child’s body. The child’s anger did not subside and it gave rise to a flame which had the power to eat up the whole world. Sages then put the flame under the ocean. This is the story of Vadavagni.
Vadavagni is located beneath the ocean and has the face of a horse. Hindu Scriptures suggest that mists and clouds are formed due to the activity of the Vadavagni under the sea. It also prevents the sea from consuming the land.
Just before Pralaya, Vadavagni will burst forth as volcanoes from under the sea and escape. Subsequently the seas will consume the land.