Word is producer Sheldon Leonard hated the script and was reluctant to give the go ahead. As it turned out, the walnuts story became the cult favorite in the entire series.
To elaborate on the atypical production would spoil the experience. So, from Feb. 6, 1963, Season 2, Episode 20, here's one I saw first-run, making for a very memorable night.
"It May Look Like a Walnut" via Hulu