Skanda Purana 7.20.226

7.20.226

kālakūṭaviṣasyotpattervistareṇa varṇanārthaṃ mahādevasya nīlakaṇṭhatāsamākhyānārthaṃ ca sanatkumāraṃ prati vyāsasyā- nurodhaḥ , kathāprasaṃgena vāyubālakhilyasaṃvādasya kumāravasiṣṭhasaṃvādasyomāmaheśvarasaṃvādasya cāvatāraṇam . umayā pṛṣṭena mahādevena svasya nīlakaṇṭhatāyā itivṛttaṃ kathayituṃ kālakūṭotpattervistareṇa varṇanam . samudramanthanotpannāt kālakūṭājjagatastrāṇārthaṃ brahmakṛtā bhavastutiḥ . brahmaṇaḥ prārthanayā surāsurasaṃghānāṃ savismayaṃ paśyatāṃ mayā lokatrayahitāya tadugraviṣaṃ nipīya kaṇṭhe dhṛtaṃ, tataśceyaṃ śrīkaṇṭhatā mameti mahādevo pārvatyai svasya nīlakaṇṭhatāyā itivṛttakathanam . brahmakṛtasya nijastavasya māhātmyavarṇanañca .

Vyāsa's request to Sanatkumāra to describe in detail the origin of the Kālakūṭa poison and to explain Mahādeva's epithet Nīlakaṇṭha. In the course of the story, the introduction of the dialogue between Vāyu and the Bālakhilyas, the dialogue between Kumāra and Vasiṣṭha, and the dialogue between Umā and Maheśvara. Asked by Umā, Mahādeva, in order to narrate the account of his own blue throat, describes in detail the origin of the Kālakūṭa. The praise of Bhava uttered by Brahmā to protect the world from the Kālakūṭa that arose from the churning of the ocean. Mahādeva narrates the account of his own blue throat to Pārvatī, saying: 'At the entreaty of Brahmā, while the hosts of gods and asuras looked on in wonder, I drank that dread poison and held it in my throat for the welfare of the three worlds, and hence this blue-throated state of mine arose.' And description of the māhātmya of the hymn in praise of himself composed by Brahmā.