Each universe
Bhagavad-gita As It Is
BG Chapters 7 - 12
BG 9.8, Purport:
This material world is the manifestation of the inferior energy of the Supreme Personality of Godhead. This has already been explained several times. At the creation, the material energy is let loose as the mahat-tattva, into which the Lord as His first puruṣa incarnation, Mahā-Viṣṇu, enters. He lies within the Causal Ocean and breathes out innumerable universes, and into each universe the Lord again enters as Garbhodakaśāyī Viṣṇu. Each universe is in that way created. He still further manifests Himself as Kṣīrodakaśāyī Viṣṇu, and that Viṣṇu enters into everything—even into the minute atom. This fact is explained here. He enters into everything.