MeanJoePhaser
Admiral
You could probably put Conspiracy in with the list of "early TNG creepfests."
You know, you don't have too many later Trek outings with the level of kind of eerie weirdness that early TNG managed to conjure. No, the Viidians don't count. I can't think of any DS9 episodes in that vein, either. Maybe Move Along Home, but obviously that was an unsuccessful attempt.
Perhaps The Assignment? Pah Wraith Keiko was kind of scary.
Not that much, while Rosalind Chao's performance is good, the pah-wraith exposition in that one was heavy. There's no mystery there.
Enterprise's "Dead Stop" comes close.