Mora Pol was originally to be played by Rene Auberjonois himself, much as Data's creator Noonian Soong was played by Brent Spiner, and as The Doctor's creator Lewis Zimmerman would later be played by Robert Picardo, but this plan was scrapped when it was realized how much time it would take each day to get Auberjonois out of one make-up and into another. Most DS9 episodes were shot in 7 days, but it was estimated that with Auberjonois playing both parts it would take at least 14 to complete the shoot.
Special effects supervisor Glenn Neufeld wasn't especially pleased with how this episode turned out, primarily due to the fact that he feels the audience sees too much of the "monster."
The appearance of Dr. Mora reflects Odo's claim made in The Forsaken (1993), when he told Lwaxana Troi that he modeled his hairstyle after the scientist assigned to him.
The life form sample that Odo and Dr. Mora find on the Gamma Quadrant planet was created by using nothing more than a clump of iron filings in a Petri dish with a magnet manipulated underneath to make it move.
James Sloyan made his first of two appearances as Dr. Mora Pol.