It's almost Halloween and it just occurs to me two of the scariest moments in Star Trek history I can remember: The Transporter Malfunction (Star Trek: The Motion Picture) Probably one of the most chilling moments in sci-fi when they attempt to beam aboard to people before having the transporters fully functional. Said people are seen barely beaming in, screaming and moaning. After a desperate attempt, they disappear. Guy on the other end says something like "fortunately, whatever came back didn't live long." If that doesn't leave some chilling visuals up to the imagination, I don't know what does. Morgue Scene (Star Trek: TNG episode Night Terrors) Beverly Crusher sees a dead body prop up on the table. Then she suddenly sees all the bodies in the morgue propped up. This was all done very quietly with no movement on the corpses part which makes the scene all the more hair raising.
The Empath was a pretty creepy episode, probably the creepiest of TOS. And agreed, the transporter malfunction in TMP was fairly graphic and horrifying.
-"In Theory," when the Enterprise is passing through a field of anomalies that create holes in the ship. Lt. Van Mayter went down a hallway, slipping off screen momentarily, and we suddenly hear her scream. When LaForge runs to her, she finds her phased halfway through the floor, which materialized through her. -"Home Soil," when Troi senses that Malcenon is in danger. Our heroes rush to his rescue, but the heavy door prevents them from saving him as they listen to repeated drilling laser blasts burning Malcenon to a crisp. (I just realized that the above two scenes have one major thing in common with the transporter malfunction in TMP: their death screams played a major, major role in making them terrifying) -The twist ending to "Bliss" was oddly a bit like the Twilight Zone -"By Any Other Name" -- I always put myself in Yeoman Thompson's shoes and imagine how horrific it must have been to be turned into a mineral cube, be conscious for the ordeal, and then get crushed to death by Rojan
I remember watching TMP for the first time as a kid and being petrified after the transporter accident. Other scenes: The destruction of the Borg Cubes at the beginning of 'Scorpion'. Not scary but definitely chilling. Also, when Chakotay, Harry and Tuvok are on the wrecked cube and you can hear 8472 screeching and ripping it's way through the ship. I also thought the Aliens from ENT 'Silent Enemy' were pretty creepy as well.
This can actually happen with the dead. It's a combination of gases in the abdomen and the release of rigor mortis, gases can make dead bodies burp and fart. The end of rigor can also result in sighing, groans and low moaning.
When I was little, the 3D holographic shadow and Geordi's fingers having transformed in "Identity Crisis" freaked me out. I've always found "Masks" eerie, although not scary.
Not so much scary as it was gory by ST standards, but the blowing up of that officer's head and chest. Head explodes and ribcage is exposed and out comes the parasite.
Sub Rosa Though to be fair to TNG, that crew-devolve one (Genesis?) is probably the nearest thing to scary. Catspaw is just too dated. The one where Garak goes loopy and nearly kills Nog isn't bad too, though not one of my favourites.
The Wrath of Khan. That thing Khan implants in Chekov... damn. Similarly, TNG: Conspiracy, particularly the ending.
Those Cardies that were left behind in stasis on Empok Nor. The Aliens in "Scientific Method". That chick that fell and was trapped between the decks of the 1701-D in "In Theory". The whole episode "Conspiracy". When the Founder in "The Adversary" tells Odo "We're everywhere". …
I still can't watch that scene and kind of cover my face for it. Somebody else mentioned the TNG episode with those parasites...eeeew! The TNG episode "Realm of Fear" kind of hits me in the nerves because I can be a bit of a hypochondriac, so I totally sympathize with Barclay's predicament! It's calmed down a lot since my teenage years, but sometimes I still freak out and run to google a weird symptom I'm having. My biggest fears are having aneurysms, strokes or bowel perforations, since all of those have happened in my family. I get ocular migraines, and I have to fight utter PANIC every time my vision gets patchy! I will run to a mirror and make sure I can smile, move all my limbs and stick my tongue straight out before deciding 'yes, Cyndi, you're having an ocular migraine. Chill out.' (It doesn't help that sometimes those migraines come with vertigo!) "A Fistful of Datas" is creepy in its own right. I mean, how scary could Data be if you messed with his programming? I find DS9's "The Alternate" to be kind of unnerving too, when Odo starts melting and turning into the creature. He sounds so terrified when you see him melting. Almost like Banner becoming the Hulk. The look on Doctor Mora's face says a lot more than a shot of the thing Odo turned into, and I found it really effective. He just looks up and his face drops, and he backs out of the security office like "NOPE!" I can't remember the title, but the episode where Bashir was unconscious and the people he saw represented aspects of his personality--CREEPY episode. Seeing DS9 looking so dark and hearing things happening offscreen, and seeing people DIE as those parts of him were shut down gave me some goosebumps.
"Distant Voices", where the Lethean did the psych attach on him. It had a Nightmare on Elm Street feel to it, with the Lethean slowly killing off his friends. A very creepy episode.