Born by Prisni’s womb (garbha).

King Sutapa and his queen Prisni prayed to Vishnu for a son like him. They uttered their prayer three times.

When Vishnu appeared before them, he announced that he would be born three times as their son.

Sutapa and Prisni he was born as Prisnigarbha.
They were reborn as Kashyapa and Aditi; Vishnu was their son Vamana, the dwarf avatar.
Kashyapa and Aditi were reborn as Vasudeva and Devaki, Vishnu was their son Krishna.

For a modified version, see Kashyapa and Aditi.

As Prisnigarbha Vishnu made Dhruva the pole star.