Vishnu’s next incarnation was in the form of a boar .GOD decided to create a creature that could live on the land alone. The boar lives on land only. This means in the order of evolution land based animals evolved. It is called Varaha Avatharam.

The mythological story behind this avathar is as follows:
Once sage Doorwasa went to vishnu -lokha to worship Lord Vishnu .But the guards at the gate - Jayan and Vijayan didn't allow the saint inside to see the lord. The sage got very angry and cast acurse that the two should leave the heavens and be born in the earth as rakshasa- cruel and violent human beings and went away .The two guards were very sad and worried. After thinking for along time they went inside and saw Lord Vishnu. They told him about the curse cast by the sage Doorvasa. However even Lord Vishnu could not reverse the curse. The guards should not have stopped sage Doorvasa at the gate. Vishnu said You both should not have stoped that sage and I can do nothing about the sage's curse but I can give a new boon that is: you both can come back to me as my enemy after 3 births or you can come back to me as my devotee after 30 births. Take your choice. They said 'O lord we don't want 30 births. Please we want to come back to you soon in 3 births even though the three births would be as your enemies'. Lord Vishnu agreed to this. So in that order their first birth is:
The sage Kashyapa and his wife Diti had two son's named Hiranyaksha and Hiranyakasibu brothers. they became the kings of the demans. These brothers were very cruel. Hiranyakasibu was the worst of the two.

Hiranyaksha’s meditation pleased LORD Brahma and lord Brahma appeared before him and granted him the boon that he would be invincible in battle. Thus armed. Hiranyaksha went out to fight with the devas. He comprehensively defeated the gods and conquered heaven. He also defeated Varuna, the god of the ocean .Thus, Hiranyaksha became the king of the heaven, the earth and the underworld. But the demons was not particularly fond of the earth. He himself had begun to live in Varuna’s palace under the ocean. So he hurled the earth into the depths of the ocean. The gods went to Vishnu and prayed that something might be done about Hiranyaksha. They wished to be restored to heaven and they wished that the earth might be brought back from the depths of the ocean. In response to these prayers, Vishnu adopted the form of a boar and entered the ocean. Who should he meet there but Hiranyaksha himself? Hiranyaksha of course did not know that this boar was none other than Vishnu. He thought that it was anordinary boar and attacked it. The two fought for many years .But finally, Hiranyaksha was gored to death by the boar’s tusks .The boar raised the earth up once again with its tusks. Vishnu thus saved the gods and the principles of dharma.