Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 18
Sanskrit:
इत्यभिध्यायतो नासाविवरात्सहसानघ ।वराहतोको निरगादङ्गुष्ठपरिमाणक: ॥ १८ ॥
ITRANS:
ity abhidhyāyato nāsā-vivarāt sahasānaghavarāha-toko niragādaṅguṣṭha-parimāṇakaḥ
Translation:
O sinless Vidura, all of a sudden, while Brahmā was engaged in thinking, a small form of a boar came out of his nostril. The measurement of the creature was not more than the upper portion of a thumb.