Ramayana
इन्द्रो मयूरः संवृत्तो धर्मराजस्तु वायसः । कृकलासो धनाध्यक्षो हंसश्च वरुणो ऽभवत् ॥ 7-18-5 ॥
Indra became a peacock; the King of Dharma (Yama) became a crow; the Lord of Wealth (Kubera) became a lizard; and Varuna became a swan.
english translation