Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 36
Sanskrit:
पुनश्च विप्रशापेन राक्षसौ तौ बभूवतु: ।कुम्भकर्णदशग्रीवौ हतौ तौ रामविक्रमै: ॥ ३६ ॥
ITRANS:
punaś ca vipra-śāpenarākṣasau tau babhūvatuḥkumbhakarṇa-daśa-grīvauhatau tau rāma-vikramaiḥ
Translation:
Being cursed by the brāhmaṇas, the same two associates took birth again as Kumbhakarṇa and the ten-headed Rāvaṇa. These two Rākṣasas were killed by Lord Rāmacandra’s extraordinary power.