An agni. He was born to Saha, an agni, and Mudita. He is also known as Grihapati and travels all over the world and purifies it, according to Mahabharata Vanaparva Chapter 22 verses 1-6.  His wife was Priya and a son was born to them called Vibhurasi.

According to Mahabharata Anushasanaparva Chapter 148 verse 108, Atbhuta is also another name for Vishnu.