Among the rarities in my collection I have the privilege, thanks to Marla Warren, to know of Michael Crichton's take on the Frankenstein archetype in his screenplay "Genes" that was never made into a movie. He wrote it in 1989.
Some 20 years earlier he was reported to be writing another screenplay called "Morton's Run", which was not made into a movie either. As far as we can tell no manuscript has been found for this one. The film trade newspaper Boxoffice reprted on May 12, 1969 that a John Lange screenplay with that title had been sold to Universal, also revealing that Michael Crichton was behind that pseudonym.
The Daytona Beach Morning Journal reported about it on July 6, 1969, on page 18, directly mentioning the author as Michael Crichton: