Does Genesis 6 teach that aliens mated with women and created a super race?

The Bible is extremely clear, most of the time. Other times, after reading a section of text, you are only left tilting your head like a hound dog who heard a whistle. Genesis 6 is one of those sections of Biblical text:

 “The Nephilim were on the earth in those days, and also afterward, when the sons of God came into the daughters of man and they bore children to them.”