Skanda Purana 7.20.224

7.20.224

brahmaṇa upadeśād devāsurakṛtaṃ samudramathanam . tadutthograviṣasya śaṅkareṇa pānam, amṛtotpattiḥ, asurairamṛtāpaharaṇam . viṣṇunā mohinīrūpamāsthāya māyayā'surānmohayitvā'mṛtaṃ pragṛhya tasya devebhyaḥ pradānam .

The churning of the ocean performed by the gods and asuras following the instruction of Brahmā. The swallowing of the dread poison that arose from it by Śaṅkara; the emergence of the nectar of immortality; the stealing of the nectar of immortality by the asuras. Viṣṇu, assuming the form of Mohinī, bewitches the asuras by his illusory power, takes the nectar of immortality, and gives it to the gods.