From startrek.website.

For those who don't remember Star Trek: Voyager, Season 4, Episode 13.

::: spoiler Tap for spoiler It's the episode where evil aliens probably inspired by Freddy Krueger force you to fall asleep and invade your dreams. The Voyager crew all share a collective dream in which the aliens control. :::

This one scared me as a kid. Revisisting it as an adult, I think it's more cool than anything. Not really scary and at times funny. Y'all liked this one? It's a neat episode.