Brahmā could see that on the water there was a gigantic lotuslike white bedstead, the body of Śeṣa-nāga, on which the Personality of Godhead was lying alone. The whole atmosphere was illuminated by the rays of the jewels bedecking the hood of Śeṣa-nāga, and that illumination dissipated all the darkness of those regions.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
मृणालगौरायतशेषभोग- पर्यङ्क एकं पुरुषं शयानम् । फणातपत्रायुतमूर्धरत्न- द्युभिर्हतध्वान्तयुगान्ततोये
mṛṇālagaurāyataśeṣabhoga- paryaṅka ekaṃ puruṣaṃ śayānam | phaṇātapatrāyutamūrdharatna- dyubhirhatadhvāntayugāntatoye
SB 3.8.23