SB 7.10.62

vatsaś cāsīt tadā brahmā
 svayaṁ viṣṇur ayaṁ hi gauḥ
praviśya tripuraṁ kāle
 rasa-kūpāmṛtaṁ papau
Word for word: 
vatsaḥ — a calf; ca — also; āsīt — became; tadā — at that time; brahmā — Lord Brahmā; svayam — personally; viṣṇuḥ — Lord Viṣṇu, the Supreme Personality of Godhead; ayam — this; hi — indeed; gauḥ — a cow; praviśya — entering; tri-puram — the three residences; kāle — at noon; rasa-kūpa-amṛtam — the nectar contained in that well; papau — drank.
Translation: 
Then Lord Brahmā became a calf and Lord Viṣṇu a cow, and at noon they entered the residences and drank all the nectar in the well.