That he made up part of the books he wrote on the Anunnaki. Here is testimony from a woman who met him.... "IN THE LATTER PART OF HIS LIFE I MET AND SPOKE WITH ZACHARIAH SITCHIN... WHO WROTE SEVERAL BOOKS ABOUT THE ANUNNAKI OR STAR PEOPLE. HE PUBLICLY ADMITTED THAT HE MADE PART OF IT UP. 
These independent translations show that he may have made a lot of it up. As we see in the depictions there were some form of gods involved in the genetic re-engineering of humanity. However it is likely that the hybrids living on the earth were superseded by the children of the Supreme Deity the I am that I am AKA Yahweh or Jehovah . Our One True benevolent God , created Adam and Lilith, but that did not work out well. So later it was Adam and Eve. But once again the fallen Angel Lucifer and others intervened and seduced Adam and Eve polluting the entire bloodline of their lineage.
That is why Jesus said he came at the last supper offering his body and blood. He also said he was grafting his disciples onto his lineage. I have explained this mystery extensively on Facebook, and you may do a search there if you're interested.
It is true that Elohim is a feminine and masculine plural word. And it represents the Seven Creative Spirits. If there were anything like the anunnaki ,they were the angelic interdimensional and interplanetary beings collectively. That is why they take so many different forms in ancient writings and depictions. There are many different hierarchies.
The Edgar Cayce readings which are highly accurate are the most complete Genesis and spiritual historical accounts ever presented. All of these issues are clarified in those readings.
It's interesting to note that in contrast to the story the native Americans( and particularly the Hopi )talk about the ant people. The word Ant is Anu! However in their creation stories the ant people took them underground where they lived to save them from Earth's surface catastrophes."
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This is so intriguing. And to think we don't even know a fraction of our true history. I'll go a step further and say what I believe; that being our species, humans, traveled to the stars and we still have not reached technology to that level.