So the people of Earth thought they had instructions from the Creator of the Universe Himself to wreck the joint. But they were going at it too slowly for the Elders, so the Elders put it into the people's heads that they themselves were the life forms that were supposed to spread out through the Universe. This was a preposterous ideas, of course. In the words of a nameless author: "How could all that meat, needing so much food and water and oxygen, and with bowel movements so enormous, expect to survive a trip of any distance whatsoever through the limitless void of outer space? It was a miracle that such ravenous and cumbersome giants could make a roundtrip for a 6-pack to the nearest grocery store.
