 When it was pitched by Marc Cushman and Jake Jacobs , the idea which formed the basis for " Sarek " featured an original character instead of Sarek . The staff writers felt the degenerative disease conceit would be a subject that viewers could relate to , as it could be a metaphor for dementia in the elderly . The element of the plot wherein the disease would cause telepathic problems for the rest of the crew was then developed , with Sarek added to the plot at a late stage in order to ensure an emotional impact on the audience . Piller said that " it brings home the idea that even the greatest of men is subject to illness " . He also said that the plot was a direct reference to the declining health of Roddenberry . The script was written by Peter S. Beagle , better known for the 1968 novel The Last Unicorn . 
