During filming of this episode, Dick York had a seizure caused by a flickering light and was rushed to the hospital. While in the hospital, York was asked if he wanted to resign from the show. Darrin does not appear again until the season finale Samantha and Darrin in Mexico City (1969) which was filmed before this episode.
This was the last show that Dick York filmed. He suffered a seizure while filming the beginning of this episode resulting in a rewrite that had him turned into a jackass. The original script for this episode was reworked as the Season 6's Darrin the Warlock (1969).
When William Asher really found out Dick York had a seizure, in this episode, before he was taken to the hospital, for real, in this episode, Asher learned going into York's hospital room, thereafter, was one of the most hardest things he'd ever done, because he knew what he had to do. York was terminated, from the series, when he was recovering from his hospital bed.