This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Star Trek: The Motion Picture
Oh, dear god, that transporter room scene. When the crewmen start re-materializing there's an odd, electronic buzz that slowly resolves (almost before you realize what you're hearing) into the sound of the victims screaming in agony. While you're realizing what that sound is, you start to notice the the two humanoids forming on the pad don't look quite...humanoid. Rand's horrified, "Oh no, they're forming!" and her turn away just adds to the horror. Watch the whole thing here.
Starfleet Transporter Tech:Enterprise, what we got back didn't live long...fortunately.
The reading of that line note A verbal dose of Heroic B.S.O.D., where the shock is so deep you can't even react properly to what you just witnessed reeeeeeeally didn't help. Gah.
The Novelization is actually WORSE. The crew members actually materialised inside out and were alive to feel it. But not for very long. Fortunately.
And then we find out what V'ger does to the "information" it collects. Poor Ilia!
And if that's not bad, try being kidnapped by V'Ger: surrounded by an incredibly strong electromagnetic /lightning type force that shocks you and anyone who tries to help you. And there's no time to cry out or to say goodbye to anyone you might care about...
"That unit no longer functions." Brrr.
V'Ger's energy weapon, which rather than blowing it's targets up or vaporizing them instantly, instead seems to methodically take it apart. We see three Klingon cruisers get slowly disintegrated this way, followed later by a Starfleet space station which just happened to be in V'Ger's path, with one person in a space suit trying to get away.
And we never learn what happened to that guy. Was he digitized and killed by V'Ger? Was he eventually crushed against V'Ger's hull, or did he spend the next several hours drifting through deep space and wondering which would come first: asphyxiation or hypothermia?
Also, V'ger doesn't so much 'destroy' a target so much as reduce it to a memory and store it within itself.
In this movie more than any other Trek production, every aspect of space travel in the 23rd Century IS TRYING TO KILL YOU! The transporter disintegrates the ship's science officer. Crewmembers make extensive use of space suits for EVA. Going to warp with the wrong kind of fault in the drive accidentally throws you inside an unstable wormhole. And remember those 300-year old space probes? One of them is coming back, and it's dragging a giant machine within a cloud millions of miles long that is more than capable of rendering the planet Earth completely lifeless. What's more, it's been sent by a race of machines that don't even perceive carbon-based organisms as living beings. V'ger is looking for God, and if it doesn't find it, it will nuke your planet.