CC Madhya 20.284

sei puruṣa ananta-koṭi brahmāṇḍa sṛjiyā
ekaika-mūrtye praveśilā bahu mūrti hañā
Word for word: 
sei puruṣa — that Personality of Godhead, Mahā-Viṣṇu; ananta-koṭi brahmāṇḍa — millions and trillions of brahmāṇḍas, or universes; sṛjiyā — after creating; eka-eka — in each one of them; mūrtye — in a form; praveśilā — entered; bahu mūrti hañā — becoming many forms.
Translation: 
“After creating the total number of universes, which are unlimited, Mahā-Viṣṇu expanded Himself into unlimited forms and entered into each of them.