The Mudgala Upanishad, along with Subala Upanishad, is one of the two Upanishads that discuss the Purusha Sukta of Rigveda. It is notable for asserting that Narayana (Vishnu) is the Brahman (Highest reality, Supreme being), that he created the universe from a fourth part of himself, then became himself the Atman (soul) in individual living beings.