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The The Star Trek Compendium lists this episode as being filmed in early and mid-October 1967 and the previous episode, "The Gamesters of Triskelion" as being filmed in late October of that same year. As with "Space Seed" and "A Taste of Armageddon" I'm not sure whether the author had the filming dates mixed up or whether post-production work was being taken into account, or if the episodes were for some reason filmed out of an assigned production order.
- I guess the author mixed it up, but in that case "The Gamesters of Triskelion" was filmed in late September. "Obsession" was surely filmed early and mid-October. The director mentions October 13, 1967 as the fifth shooting day in his blog. -- Ltarex, June 9, 2010, 9:21 (CET)
I rewrote the two items listed under the subsection "Cast."
- * Eddie Paskey (Lt. Leslie) is killed by the vampire cloud in this episode, but reappears in later scenes (and the very next episode "The Immunity Syndrome") very much alive! According to Paskey, a scene in which a miracle potion saved his life was cut from the show. To see Leslie post mortem, look to see him walk by McCoy in a corridor in a red shirt. Later he walks by McCoy's office door in a yellow shirt when Nurse Chapel enters.
The exclamation point had to go, and the POV was all wrong in the next-to-last sentence.
- * Jerry Ayres, who is killed by the vampire cloud, ...
Good lord, I hope Mr. Ayres wasn't killed, but rather his character was. -- Bridge 11:42, 5 May 2008 (UTC)
"no natural phenomenon can move faster than light" Edit
In a different episode - and I'll need some reminding as to which one - we are told that no natural phenomenon can move faster than light. Yet the cloud-creature in "Obsession" reaches speeds up to warp 8. --220.127.116.11 05:18, 15 May 2008 (UTC)
- that would be from this sites namesake episode "The Lights of Zetar". --Morder 05:55, 15 May 2008 (UTC)
- perhaps no existing natural phenomenon, since the dikironium cloud creature clearly did not walk away from this episode. 18.104.22.168 08:51, 4 March 2009 (UTC)
Removed the following nitpick.
- (NOTE: This requires an explosive force of more than 4.6 million megatons. This is far beyond the standard formula for an ounce of anti-matter, which renders a reaction of no more than 2 megatons. This indicates that Star Trek's anti-matter reactions use a much greater standard than current-- more than 2 million times greater.)
- I also removed this as a nit. - Archduk3 05:55, June 9, 2010 (UTC)
I removed the sentence about the octopus from the end of this section in Story and Production,
- This episode also reveals more about the biochemistry of Spock, which is based on copper, not iron, and found to be distasteful to the creature. On our own planet, octopuses have copper-based blood, hemocyanin, which makes their blood appear blue.
Mrtrekkiedude 12:30, August 6, 2011 (UTC)