Catspaw
A previously-uninhabited world is now home to a variety of objects and creatures drawn from . . . Halloween? Kirk and Spock battle beings who probe the human subconscious to create their world.
Many people see this among the bad episodes, but we figure, it's meant to be silly and fun, and it is. (The truly bad episodes are either boring or unintentionally silly.) For things that are supposed to be new and frightening, much is familiar. Again, Kirk and Spock are locked in a dungeon as in Return of the Archons and others, again there is a lavish dinner with an eccentric host, as in The Squire of Gothos. The giant cat is pretty novel though, both creepy at first then hilariously cheesy. Slyvia's "many women" scene amuses too, since it's just her in a series of ugly wigs and dresses. The feather creatures are great in their own way - you can see the strings. The theme of beings seeking sensation is done better in By Any Other Name, but well established here. The best guilt-free laughs are provided by some subtle lines, like the "bad poetry" exchange and Kirk addressing Bones, then Doc, when he realizes he's next to a skeleton. The ship scenes are dull compared to what's goin' down on the surface. But the fun wears out even there. Star Trek junk food.
Spock Saves the Day: Spock offers many tricorder readings, helps Kirk get the transmuter, and fends off the giant cat.
Oops: Halloween seems a significant holiday strangely omitted from the Vulcan's cultural studies of Earth.
Developments: Spock knows precisely how long they've been in the dungeon, with the "clockwork ticker" in his head. His other abilities don't seem especially useful against the creatures of the night. Nor are any of these images from his subconscious; Kirk provides it all. I'm sure Spock's got some interesting and even frightening stuff lurking in the back of his mind, but keeps it well guarded.