Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 53
Sanskrit:
तस्मिन् महाभोगमनन्तमद्भुतंसहस्रमूर्धन्यफणामणिद्युभि: ।विभ्राजमानं द्विगुणेक्षणोल्बणंसिताचलाभं शितिकण्ठजिह्वम् ॥ ५३ ॥
ITRANS:
tasmin mahā-bhogam anantam adbhutaṁsahasra-mūrdhanya-phaṇā-maṇi-dyubhiḥvibhrājamānaṁ dvi-guṇekṣaṇolbaṇaṁsitācalābhaṁ śiti-kaṇṭha-jihvam
Translation:
In that palace was the huge, awe-inspiring serpent Ananta Śeṣa. He shone brilliantly with the radiance emanating from the gems on His thousands of hoods and reflecting from twice as many fearsome eyes. He resembled white Mount Kailāsa, and His necks and tongues were dark blue.