While early humanity was carrying out's G-d's purpose for them, there was some extra-terrestrial immigration. A group described as 'the sons of God' were attracted to the women of earth. Like Eden, when Satan seduced Eve, these sons of G-d visited earth seduced and wooed humanity's females. Then there were intermarriages between these extraterrestrials and humanity. According to at least one very reliable source in the literature of the Apocrypha (the book of Enoch), those alien immigrants brought with them the magic arts, cosmetology, astrology, herbal medicine, technological know how and many of the things (and sins) that humanity now practices. Note well that: The book of Enoch is reliable because this same book is cited in the New Testament book of Jude verse 14-15 and also by a respected Ante-Nicene father of the early church, Iraeneus (Schaff p.481).
As a consequence, there were mutants born among the human race. Giants and men with incredible powers, abilities and capabilities occupied the earth, as cross-breeds between humans and fallen angels (the aliens) (Genesis 6:4).
On reading this, I believe that some of you are probably thinking that this is a wild interpretation closer to Hollywood. Unfortunately, Hollywood's motion picture ideas are not very far fetch from spiritual reality. In fact, though I don't have sufficient documentary proof, I believe that some of Hollywood's movie ideas are obtained by necromancy or by demons/fallen angels communicating with Hollywood movie directors, actors, script writers and other artists. That however may be an entirely new area of research that is outside of the scope of this reflection.
Schaff, Philip. ANF01. The Apostolic Fathers with Justin Martyr and Irenaeus: Christian Classics. Grand Rapids, MI: Christian Classics Ethereal Library, 2002. Web. 4 June 2011. <http://www.ccel.org/ccel/schaff/anf01.pdf>