SB 12.4.4

eṣa naimittikaḥ proktaḥ
 pralayo yatra viśva-sṛk
śete ’nantāsano viśvam
 ātmasāt-kṛtya cātma-bhūḥ
Synonyms: 
eṣaḥ — this; naimittikaḥ — occasional; proktaḥ — is said; pralayaḥ — annihilation; yatra — in which; viśva-sṛk — the creator of the universe, the Supreme Lord, Nārāyaṇa; śete — lies down; ananta-āsanaḥ — upon the snake-bed of Ananta Śeṣa; viśvam — the universe; ātma-sāt-kṛtya — absorbing within Himself; ca — also; ātma-bhūḥ — Lord Brahmā.
Translation: 
This is called the naimittika, or occasional, annihilation, during which the original creator, Lord Nārāyaṇa, lies down upon the bed of Ananta Śeṣa and absorbs the entire universe within Himself while Lord Brahmā sleeps.