Bhagavatapurana 10.18.25

10.18.25

aviṣahyaṃ manyamānaḥ kṛṣṇaṃ dānava-puṅgavaḥ /
vahan drutataraṃ prāgād avarohaṇataḥ param //

Thinking Kṛṣṇa to be unassailable, the foremost of Dānavas / carried [Rāma] and went very swiftly past the point of dismounting.

25. The great asura knowing Krishna to be unbearable (irresistible) for him ran in great swiftness far beyond the point, bearing his burden (Rama) before setting him down. 26. Bearing Balarama on his back, he (the great Asura) slackened his speed and assumed his own asura form huge like a mountain, and, decorated with golden cloths, the great asura shone like a cloud illumined with flashes of lightning and with the moon riding over it.

10.18.25.p1

tam udvahan dharaṇi-dharendra-gauravaṃ $ mahāsuro vigata-rayo nijaṃ vapuḥ &

Bearing him who possessed the weight of the greatest of mountains, the great asura lost his speed and assumed his own form;