* Skull Reaper, the very last boss that they fight, [[spoiler: just before the reveal that Heatcliff was actually Kayaba]], pictured to the right. No wonder everyone was running away in fear.
** It's actually much worse than it looks. It killed several players with a OneHitKill attack.
* The entire premise of the ''Aincrad'' arc. 10,000 people think they signed up for a game, and instead they were really signing up for a war, and they don't even get to go through basic training first. As many of them die in the first month as do in the next two years. EverythingIsTryingToKillYou, and even some of the players start murdering each other. Basically, the entire ''Aincrad'' arc is scary.
* In ''A Murder Case in the Area'', [[spoiler:Grimlock arranged the murder of his guildmaster and ''real life wife'' Griselda because she actually rose to the challenge that SAO provided and she was no longer as [[ExtremeDoormat submissive and dependent on him]] as she used to be IRL.]]
* The opening to Episode 15. Everything's nice and calm and peaceful. And then the world breaks.
* When people come out of their virtual imprisonment, both in SAO & ALO, they're disoriented, their muscles are atrophied, etc. They're helpless. Think about what would've happened if [[spoiler: [[FridgeHorror Kirito hadn't stopped Sugou's knife attack outside the hospital where Asuna just woke up. After he'd already declared he was going to rape her while comatose.]]]]
* Poor Asuna. Her example actually crosses with FridgeHorror if you analyze what she had to go through. First off, it is implied she may have had no experience with gaming ever before, since, in her misfortune she got into SAO out of curiosity by borrowing her brother's [=NerveGear=] (who could not play on the first day), only to find out she is stuck [[spoiler:for over two years]] in a virtual world where there's death around every corner. Just look how mentally broken she is when introduced early in the story. [[spoiler:And then, after SAO is completed, what next? Instead of finally achieving her freedom, she is imprisoned inside another game by a friend of her family, who turns out to be an AxCrazy pervert threatening her to rape and brainwash her into submission.]] Kirito is the only thing that keeps her sane.
** Now think about Asuna's brother. He lends his little sister a game while he was away, only to find out that she was caught in a trap meant for him. And of course, his situation is obviously not unique. How many parents and older siblings gave Sword Art Online to children as a gift? How many of those children died because of that gift? Survivor guilt ain't limited to the SAO players.
* When Asuna's former escort [[spoiler: reveals to be an AxCrazy killer who almost suceeded in murdering Kirito. All with a poison that paralyzes him.]] Thank goodness Asuna had Kirito on her friend list.
* Sugou might as well be the most sadistic asshole to walk the earth. Basically, just before his defeat, [[spoiler: [[MoralEventHorizon he molests Asuna after stripping her. IN FRONT OF KIRITO.]]]]
** Not to mention that if [[spoiler: Sugou hadn't been stopped by Kirito, he would have raped Asuna, who was ''in a coma,'' in her hospital bed.]]
** The [[spoiler:threat of rape]] is bad enough. But then there's also that he was almost certainly planning to use his [[spoiler:mind control technology to make her love ''him'' (or some sick alternative) by manipulating her emotions and even '''altering her memories''', which may also have included '''''completely erasing her memories of Kirito'''''! And there's no telling what he might have done to Kirito himself.]] A CompleteMonster indeed.
* [[spoiler:Sugou's injuries from Kirito curb-stomping him in ALO were pretty gnarly. Before said beatdown, Sugou warned Kirito, while torturing him, that when the game's pain inhibitor dropped below level 3, it would affect his body in the real world. Then Kirito gets administrative control over Sugou and set his pain inhibitor to '''''zero'''''. When Sugou appears in the real world trying to kill Kirito, he's going partially blind in one eye and has just about dove off the deep end. Granted, [[KickTheSonOfABitch the son of a bitch had it coming]], but still...pretty gnarly.]]
* Death Gun. To the average person, the idea that they could die in a game is already frightening. To SAO players, it's basically living through the infamous "death game" all over again, [[spoiler: especially since two of the people behind Death Gun were members of Laughing Coffin]].
** What's even more scary is the secret behind how Death Gun kills. [[spoiler: Someone breaks into your house and gives you a lethal injection. If your consciousness is inside a game, [[FridgeHorror what's protecting your body]]?]]
*** [[spoiler:And the threat doesn't have to be malicious, either. What happens if your house catches fire? You won't even hear the smoke detector!]]
* The deaths of the Black Cats, specifically Ducker, who is swarmed by Dark Dwarves who immediately butcher him with their pickaxes, with Ducker screaming horribly with each hit until he finally dies.
* Anti-crystal zones: Traps where deadly monsters attack players who are unable to retreat because their teleportation crystals don't work. It gets worse: they're not anti-teleportation zones, they're anti-crystal zones, which means that healing crystals don't work either. SAO was already dangerous enough, but these traps (including some boss chambers, which are unavoidable) disable a player's two most important lifelines: the ability to flee by teleportation and the most efficient means of healing.
* Sinon's BloodKnight tendencies are bad enough that Kirito actually suspects her of being Death Gun.
* Kirito's memories of the members of Laughing Coffin he killed haunts him to no end in Season 2, Episode 7. [[http://img4.wikia.nocookie.net/__cb20140816181141/swordartonline/images/3/31/Crimson_Memories.png This image pretty much speaks for itself.]]
** Sinon's aren't any better. Just look at when she saw that Death Gun's signature gun [[spoiler: was the same one she used to kill the bank robber years ago.]]
* Death Gun paralyzes his victims before killing them. Kuradeel also implied that this was a common tactic in Laughing Coffin. The victims were fully aware of what was happening and completely helpless.
** And In-Universe, the idea that while Death Gun is trying to kill you in the game, [[ParanoiaFuel another one is waiting in your room/apartment/whatever, just waiting for the right moment to inject you]] - and you're unable to do anything about it at all. The sheer imagery of this attempted murder is enough to send Sinon into a near panic-attack.
* The look on [[spoiler:Kyouji's face as he's proposing to Shino. It's at this point it becomes clear that he's totally lost it. Shino did tell him to wait for her and was probably sincere, but she wasn't expecting him to be this when the time came. After she pushes him away, he decides that since she won't have him, he'll just rape and kill her, then kill himself to join her in the next life, but not before confessing the entire Death Gun conspiracy to her. It's more terrifying when you look at his face before Kirito manages to save her in a nick of time.]]
** The most unsettling thing of the above is that [[spoiler: Shino was almost raped by someone she had known and trusted for ''years.'' Even worse, unlike the situation with Asuna and Sugou, she got along really well with Kyouji and enjoyed being around him. It reflects the grim reality that many, many rapes in real life are done not by complete strangers, but by somebody the victim is well-acquainted with.]]
* The fact that of the SiblingsInCrime in the Death Gun conspiracy, the one who came up with the idea was the one who wasn't an SAO survivor.
* Kirito's severe depression in Red Nosed Reindeer. Even before he turns explicitly suicidal and resolves to banzai charge the bosses, he's displaying multiple warning signs of contemplating suicide: brazenly reckless behavior, insomnia, and cutting himself off from what few friends he has. Even scarier is the fact that this stuff is real: severe, untreated PTSD can easily degenerate into severe depression and suicide.
* Infinity Moment/Hollow Fragment
** The increasing frequency of traps in the last few floors count as [[JumpScare Jump Scares]] even if the player has little chance of actually dying.
** [[spoiler:The 2nd and 3rd rounds of the Floor 100 boss. In the 2nd round, you have a bunch of UncannyValley MHCP with [[RedEyesTakeWarning glowing red eyes]] trying to kill you. In the 3rd round, you have to fight a [[FanDisservice giant mutant Strea]].]]
** [[spoiler:The situation with Sugou/Alberich is even worse than in canon. Not only is he able to abuse GM privileges to sexually harass and kidnap players like in ALO, he can now take advantage of the fact that he's in a DeadlyGame to actually kill people via a slow and incurable poison. Worse yet, Kayaba is too busy dealing with glitches and such to stop him, meaning the raid team would have been screwed without Strea's HeroicSacrifice.]]
** Asuna worries that if all the blame is shifted on Kayaba, people like [[spoiler:Sugou]] could [[KarmaHoudini get away with their crimes]] and retaliate against them. She's ProperlyParanoid considering the post-Aincrad events in canon, especially in the case of the Laughing Coffin.
** In the sidequest to recruit [[spoiler:Hollow Sachi, you have to enter a room that looks suspiciously like the one where the real Sachi died. Then you have to fight off two mobs that can easily kill Hollow Sachi if you didn't level her first, effectively recreating that nightmare scenario.]]
* How about sleep-[[PlayerKilling PK]] in SAO? Towns and other settlements are supposed to be safe zones where nothing can lower your HP, other than dueling, which requires your explicit consent. Thus, while within one you can rest easy, knowing you're never in danger. And this is critically important when what you initially thought was only a game has become something that could really [[AllDeathsFinal cost you your life]]. And then, one day someone [[LoopholeAbuse discovers a way around it]], which involves exploiting the duel system: just by sneaking up on you while you're asleep and moving your finger to touch the popup window, they can fool the system into believing you've accepted a duel, and proceed to murder you while you're most vulnerable. And the worst part? Unlike in the real world, you [[DeepSleep might not wake up even while under attack]].[[note]]It doesn't help that players are not made to feel any pain, which, while undesirable for having fun in a mere game, could be literally a life saver in this scenario.[[/note]] So now you have to [[ParanoiaFuel live with the knowledge]] that even in a supposedly "safe" zone, if you've pissed off the wrong person, or have an item worth killing for, or you're just plain unlucky, you just might [[SlainInTheirSleep go to sleep and that would be the last thing you ever knew]].