SB 4.17.34

sa vai bhavān ātma-vinirmitaṁ jagad
bhūtendriyāntaḥ-karaṇātmakaṁ vibho
saṁsthāpayiṣyann aja māṁ rasātalād
abhyujjahārāmbhasa ādi-sūkaraḥ

saḥ—He; vai—certainly; bhavān—Yourself; ātma—by Yourself; vinirmitam—manufactured; jagat—this world; bhūta—the physical elements; indriya—senses; antaḥ-karaṇa—mind, heart; ātmakam—consisting of; vibho—O Lord; saṁsthāpayiṣyan—maintaining; aja—O unborn; mām—me; rasātalāt—from the plutonic region; abhyujjahāra—took out; ambhasaḥ—from the water; ādi—original; sūkaraḥ—the boar.

My dear Lord, You are always unborn. Once, in the form of the original boar, You rescued me from the waters in the bottom of the universe. Through Your own energy You created all the physical elements, the senses and the heart, for the maintenance of the world.

This refers to the time when Lord Kṛṣṇa appeared as the supreme boar, Varāha, and rescued the earth, which had been merged in water. The asura Hiraṇyākṣa had dislocated the earth from its orbit and thrown it beneath the waters of the Garbhodaka Ocean. Then the Lord, in the shape of the original boar, rescued the earth.