Dutiyasutasutta

Sāvatthinidānaṁ. Ekamantaṁ nisinno kho so bhikkhu bhagavantaṁ etadavoca: “ko nu kho, bhante, hetu, ko paccayo, yena midhekacco kāyassa bhedā paraṁ maraṇā jalābujānaṁ nāgānaṁ sahabyataṁ upapajjatī”ti? …pe… Ayaṁ kho, bhikkhu, hetu, ayaṁ paccayo, yena midhekacco kāyassa bhedā paraṁ maraṇā jalābujānaṁ nāgānaṁ sahabyataṁ upapajjatī”ti. Aṭṭhamaṁ.

At Sāvatthī. Seated to one side, that mendicant said to the Buddha: “Sir, what is the cause, what is the reason why someone, when their body breaks up, after death, is reborn in the company of the womb-born dragons?” (Tell all in full.)