Shiva Purana
पुनश्च मथ्यमाने तु कालकूटं महाविषम् ॥ युगान्तानलभ जातं सुरासुरभयावहम ॥ १९ ॥
When it was churned again, the great poison Kālakūṭa blazing like the fire at the dissolution of the Yugas and terrifying the gods and the Asuras, came out.
english translation
punazca mathyamAne tu kAlakUTaM mahAviSam ॥ yugAntAnalabha jAtaM surAsurabhayAvahama ॥ 19 ॥
hk transliteration by Sanscript