When I was a kid, "Schisms", "Identity Crisis" and "Genesis" freaked me out.
Now they're warm and fuzzy nostalgic memories
Now they're warm and fuzzy nostalgic memories

All of the Lwaxana Troi episodes, klingon politics episodes and any episode requiring Marina Sirtis to act outside of her limited range. Also The Host, because of Crusher and Riker bumping uglies
They changed that in the German version: The signal became a warning about humanity!Conspiracy due to the homing beacon at the end.
That holodeck scene with the shadow reconstructing a gray blob out of nothing was just as creepy as the Schisms clicks"Identity Crisis"
I'd like to throw another ep out for consideration, one I've just finished watching - Timescape. It's not as overtly creepy as others, but there's something distinctly unsettling about it throughout, thanks to nice build-up and pacing of reveals as the mystery unwinds, and the visually unnerving tableaus of frozen ships and crews. Another example of quiet and restraint working well.
We use essential cookies to make this site work, and optional cookies to enhance your experience.