And for the purpose of killing the Danavas Lord Vishnu passed a long time indisguise in the womb of Aditi (mother of gods) before taking his birth simulating the form of the Hayagriva (horse-necked).
विष्णुनाश्वशिरः प्राप्य तथादित्यां निवत्स्यता। गर्भ वधार्थं दैत्यानामज्ञातेनोषितं चिरम्॥