Lost/Nightmare Fuel

"Michael: I though you said there were 23 of you. Libby:...there were."
 * The opening title music.
 * The early episodes of the series set the course for all kinds of spooky. I mean, the monster eats the pilot in a far more gruesome manner than what would later be canon. Certainly you must've gotten chills when Jack, Kate, and Charlie are visiting the cockpit. And the first time we see a dead person walking around the island (Christian) is very creepy indeed.
 * Jacob's cabin, for one.
 * Jacob himself, for two.
 * Except that wasn't him. We now know it was The Monster. I'd still like to know who the other guy was, though, the guy whose eye we saw.
 * It was Christian.
 * "Teresa falls up the stairs, Teresa falls down the stairs..."
 * Just about anything to do with the hatch button, although the Swan training film is particularly notable in its creepiness.
 * The terrifying moment when . Add to that  ...
 * The dynamite at the end of season 1. ** And if that wasn't enough, in season 6
 * "I'm sorry you had to see me like that." So are we.
 * After  several characters begin experiencing "time flashes" which are accompanied by a blinding flash and a increasingly loud noise that sounds like chimes, followed by a whooshing sound and magnetic humming. Hear it here.
 * Ben is terrifying at times. That creepy unblinking stare of his... *shudders*
 * "YOU KILLED MY DAUGHTER!" Although it's a CMoA for Ben, it doesn't change the fact that it's absolutely TERRIFYING.
 * In Season 2, when he was a prisoner: How scary are you when you're tied up in a cell repeatedly getting the crap beaten out of you every other episode, and you can STILL give people nightmares?
 * "You guys got any milk?"
 * "THIS PLACE IS DEATH"
 * After spending the first five seasons being scared to death of the black smoke monster, there's something very unnerving about.
 * The look on  when he sees the little boy. He actually looks scared, which given what he is and what he's capable of is spine chilling.
 * And for that matter,  himself.
 * The entirety of the Season 6 episode "Sundown", especially
 * For me it was when  Also,   "He's coming Kate! He's coming and they can't stop him!"
 * Also from "Sundown",  When Ben is creeped out, you know something's terribly, terribly wrong. It was also just slightly awesome.
 * Considering what a creepy Ax Crazy Complete Monster the guy is, . There was something very odd about his eyes -- maybe contacts, maybe just lighting -- which sent him into the Uncanny Valley. Maybe it's the fact that this particularly evil monster is actually smiling. You know something's wrong when he's cheerful.
 * But you must admit, he makes great eggs.
 * The scene where
 * Claire's "baby". That she knows it isn't real somehow makes it worse.
 * Going back to the earlier seasons, in the pilot episode the Losties first get the radio working and hear a transmission in French. After a couple seconds of them cheering that the French are coming to rescue them, Shannon translates the transmission which says in part: "The others are dead. It killed them. It killed them all. It is outside." The Mood Whiplash makes an already creepy moment that much more chilling.
 * It doesn't help that the counting voice sounds just like a number station (google it, they're creepy).
 * Fridge Logic says that's probably exactly what the radio broadcast of the numbers was originally set up as.
 * In the episode "Dr. Linus",.
 * Nikki and Paolo being buried alive, especially when Nikki opens her eyes just in time to have a face full of dirt thrown in it. Even Scrappies don't deserve that.
 * Huh, you know this island really isn't that bad. Beautiful landscape, good weather, no wild anim-OH DEAR GOD POLAR BEARS!
 * So, as of Everyone Loves Hugo, we know what the whispers in the jungle are... knowing doesn't really make it less scary. In fact, it kind of makes it worse when you consider how many distinct voices you can pick out of the whispers.
 * Well, The Candidate provides us with the possible horrors of
 * What They Died For, the penultimate episode, gives us the incredibly creepy confrontation between the Un!Locke and . There are no explicit scares, just an all-encompassing sense of dread that starts as soon as "Locke" arrives, still looking and acting as he has in seasons past, but also...not.
 * The ending of The End gives us a pretty bad bit of Fridge Horror.
 * There is some hope however,
 * Locke's strangely horrifying line
 * At Lostpedia they make the case that.
 * Or perhaps he's sort of junior emissary, not unlike Clarence in It's a Wonderful Life. But yes, it was pretty spooky when Locke said that to Jack, since it's at that moment when what's going on in the "alternate timeline" (HA) really starts to become clear.
 * Claire's nightmare from Season 1, especially Locke's eyes.
 * The scene in which it's confirmed that Ethan Rom wasn't actually one of the plane crash survivors. Going straight from discovering his name wasn't on the manifest and realizing you have no idea who or what he really is to seeing him standing over the alone, defenseless Claire gave me nightmares for weeks.
 * That oh so very creepy smile he gave Claire and Charlie in that scene should send chills of terror up and down your spine whenever you see William Mapother, regardless of the context.
 * The accompanying slide trombone sound effect makes it even more eerie.
 * The season 2 episode when Sayid is interrogating "Henry Gale": "My name is Sayid Jarrah, and I am a torturer." The creepy music and Naveen Andrew's emotionless delivery makes it absolutely chilling, coupled with sudden look of Oh Crap on  face as he realizes Sayid isn't bluffing...
 * Fridge Logic adds another layer. Ben knows exactly who Sayid is, and should have known what he's capable of. The fact Ben is scared means Ben made a conscious decision about what risk Sayid posed to him at this point, and has just realized he made the wrong call.
 * On a "List of Things You Don't Want to Hear When You're Tied Up and Locked in a Room Alone With Another Person," this ranks pretty high...
 * "I don't know what is more disquieting: the fact that the rest of the statue is missing, or that it has four toes."
 * The episode where Michael, Jin, and Sawyer are :
 * The episode where Michael, Jin, and Sawyer are :


 * "Did you just call that... thing?!"
 * One episode ended immediately after Michael . Wham.
 * Room 23. Watching Karl being strapped to a chair, drugged, and forced to watch a bizarre video with loud music blaring in his ears and weird clips of seemingly random images are seen flashing on the screen (one of the images consists of several, creepy doll faces) is disturbing.
 * On that note, have you ever listened to the music of Room 23 played backwards?


 * The crash of Oceanic 815 flight is shown in only bits and pieces but if you watch it edited together like it was the opening of the show you can see how violent and terrifing the crash actually was.