Below, there is another excerpt frpm Pages 364 - 365 of Alien Identities:
"There is one example, however, of an attempt by Daityas and Danavas to take over and rule human society, and this forms the main plot of The Mahabharata.
The story begins a long time ago, when human society was prospering. people were dedicated to principles of virtue, and they did not decline into decadence as they began to experience material success. However, this auspicious situation did not last. Just as in the story of the Kaleya Danavas, human society began to be affected by events occuring in celestial planetary systems. Here is what happened, as narrated by King Janemejaya by the sage Vaishshampayana:
'But then, Oh best of Monarchs, just as humankind was flourishing, powerful and demoniac creatures began to take birth from the wives of earthly kings.
Once the godly adityas, who administer the universe, fought their wicked cousins the Daityas [demoniac creatures] and vanquished them. Bereft of their power and positions, the Daityas began to take birth on this planet, having carefully calculated that they could easily become the gods of The Earth, bringing it under their demoniac rule. And thus it happened, Oh mighty one, that the asuras [also demoniac creatures] began to appear among different creatures and communities'.
As these demoniac creatures continued to take birth upon The Earth, the Earth herself could not bear the weight of their presence. Having fallen from their positions in the higher planets, the sons of Diti and Danu thus appeared in this world as monarchs , endowed with great strength, and in many other forms. They were bold and haughty, and they virtually surrounded the water-bounded Earth, ready to crush those who would oppose them.
They harrassed the teachers, rulers, merchants, and workers of The Earth, and all other creatures. Moving about by the hundreds and thousands, they began to slay the Earth's creatures, and they brought terror to the world. Unconcerned with the godly culture of the brahmins, they threatened the sages, who sat peacefully in their forest ashrams, for the so-called kings were meddened by the strength of their bodies'.
In response to this invasion, Bhumi, the Earth goddess, approached Lord Brahma and asked him to save the Earth. Brahma responded by ordering the devas to encarnate of Earth just as the Asuras [demoniac creatures] had done: ...
In due course of time, various Devas [pious celestials] appeared on the Earth, either by entering personally into the wombs of earthly mothers or by impregnating earthly women and producing offspring that partook of their own nature. Then Lord Vishnu appeared as Krishna, the son of Vasudava and Devaki.
Several points can be made about this complex story. The first point is that at the present time, much has been written about beings from other planets who reincarnate in human bodies as 'Wanderers' from other planets who reincarnate in human bodies with the aim of carrying out some higher purpose. There is also talk of 'walk-ins', or souls that take over the existing bodies and displace their original souls. These souls are similar to the idea presented in the Mahabharat that the Devas [pious celestials] and Asuras [demoniac creatures] could take birth on Earth with specific missions to perform".
Alien Identities: http://richardlthompson.com/book/alien-identities-0