"The Last Mimzy" is loosely based on the classic science fiction short story "Mimsy Were the Borogoves" by Lewis Padgett, the pen name of collaborators Henry Kuttner & C. L. Moore; the story appeared in John W. Campbell's magazine "Astounding" in 1943. The only elements retained from the story are the toys sent back through time, teaching the children advanced thought patterns and mental abilities through play. The purpose of the toys is entirely different, and the tragic ending of the original story is eliminated.