Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Nightmare Fuel: Yogscast Minecraft Series
Shadow of Israphel:
Poor Granny_Bacon being transformed into a zombie by Israphel, and ruthlessly attacking Simon and Lewis while doing The Slow Walk. As if that isn't enough, she becomes more bloody and zombie-like the more damage she takes, until she is entirely green and skinny, with exposed flesh, bones, and a chilling snarl.
Israphel in general. A...something...with an unnaturally vengeful desire to kill all the Antiochs, who kidnaps kids and corrupts anything and anyone.
The area under the tree in Shadow of Israphel Episode 29 where Vitali hid the remains of his victims.
The descriptions of how he killed the individual Skylords is genuinely terrifying, and is a rare moment where no comedy is inserted. Also the fact that's he's a freakin' vampire.
The possible Bad Future seen in Shadow of Israphel episode 25.
Rory Rockhammer's flaming transformation into a zombie-thing controlled by Israphel.
Episode 34. The world is ending in 3 days, 7 hours.
Episode 35. Discovering that Knight Peculier was this damned close to killing himself and Xephos and Honeydew when they first met. Especially horrific when you think back to how amused Simon and Lewis were to have discovered a village with the archetypical RPG Barkeeper.
You remember when Simon and Lewis were suspicious of the milk he gave them at first? They were almost right.
The group finding an entire town buried and suffocated under the sands.
In Episode 36, the last letter cutscene shows a black hand, rising from the sands, and then a wave of sand covering Terrorvale.
And we soon, unfortunately, find out what said hand contains. See entry below.
In Episode 37, Honeydew dies twice. Something about one of the heroes failing so close to the end is pretty unsettling.
Episode 38. The apocalyptic log given by Enoch, ending with a giant fucking bloodstain. And Israphel won't stop scaring the shit out of you.
Enoch going insane and killing the remainder of his party. He kills the first by stabbing them in their sleep, then pushes Scribe_Anno into a radioactive stream.
The part right before the bloodstain with Israphel and the audio distortion DID NOT HELP.
Making it even worse is the source of the death. Radioactive lava.
"The Sentinels are active".
Which makes you wonder. What the HELL are the Sentinels?!
According to the episode, the giant hand was buried underneath the sand and was only starting to regenerate AFTER the sand was cleared out of it. Does this mean that Minecraftia has two horrible unnatural abominations (The sand and the black metal/Sentinals) and one is only slightly better than the others!?
The giant metal hand growing back by itself.
Some of the music used is pretty unnerving, such as "Kingdom of Lies."
"Off The Deep End" isn't any better.
Episode 39 is much more comical in comparison to the previous one, but there are still quite a few notable moments:
The exploration of the lair eventually reveals the sound of a very disturbing heartbeat.
The duo stumble across a cloning facility; as usual the experiment is revealed to have gone wrong, with all future clones going insane, losing most higher brain function and then going Axe Crazy.
To make matters worse, Simon clones himself, which causes him to be trapped and frozen alive for a minute or two.
The Evil_Honeydew twin clones are funny, but the pair are basically a demonstration of what Simon would be like if he was evil. The pair take Mad Bomber to the extreme, have very twisted and deranged speech patterns and nearly destroy entire sections of the relic twice. And while one was taken down, the other is still wandering free.
Despite a history of making light of horror maps, even Simon and Lewis couldn't make Wintertide less horrifying. Possibly helped by the fact that they genuinely didn't know what they were in for and expected another kooky Christmas themed map instead of... thatthing.
Although the creepy notes are... not so creepy considering Simon 1) read them out in his Griswold voice and 2) it was supposed to be a little girl. Actually, if he had used the appropriate voice it likely would ha Simon's little girl voice can be god damnterrifying.
The creepy voices they used to read the notes in Monarch of Madness. Doesn't start until the "madness" is evident, but when it does...
Whenever they do creepy voices in general, and the music inserted doesn't help...
The aftermath of the Tekkit War, which has the entire server in ruins.
The Helicopter mod spotlight has an earlier segment where Lewis is set up for execution. Thanks to the Pincushion mod, he has tons of arrows sticking out of him that don't disappear.
Chronotide is turning out to be this. The worst was episode 3. We'd allready seen a villager vanish without a trace, but once they both see them, things become very tense. And after two power cores going without too big a hitch, nobody expected the blood curdling scream as twelve Blazes suddenly fall from the ceiling. After the long build up of tension, that was genuinely terrifying to the extreme.
The main villain's voice was freaky as well.
In the Tekkit Chronicles, Sjin kidnaps Teep(who is a mute dinosaur) and threatens to eat him. Coupled with the fact that he is the TRUE ruler of Sips Co, Sjin may be the Big Bad of Tekkit...
The end of Rythian's Tekkit: Season 2, Episode 17. Imagine this: There's a nuke of deadly power beneath your home. You've reassured your friends that you can deal with it, but you know inside yourself that you don't know enough. You send them far away so they won't get hurt if you fail. You reassure yourself that you can do it. You cut the wrong wire. The bomb starts to beep, increasing in frequency. In your last seconds you cry out for your friends, but they're not there. There's no one to hear you, or to rescue you from the inevitable. The nuke explodes, and it's all your fault.
Or this: After a huge fight and a long time apart, you've finally reunited with the person you love. The two of you have talked through your issues, and things seem to be finally looking up. They announce they're going to defuse the deadly nuke and save your home, and assign you to protect all of your other friends. They assure you that they'll be fine and they have everything under control. After repeatedly offering to stay with them you reluctantly agree to leave, making them promise to be careful. Worried, you're in the process of shepherding all your other friends out of the danger zone when suddenly you hear an Earth-Shattering Kaboom behind you...
In the Herobrine's Mansion series, Simon's voice for the Wither is rather high-pitched and wavery. Funny... Until you realize that IT'S THE SAME VOICE USED FOR ENOCH IN SHADOW OF ISRAPHEL.
The 12th part of the Voltz series is mostly hilarious, following the events that transpire after Sips and Sjin set off a Red Matter bomb that creates a black hole. But when helping them, Ridgedog says something extremely desperate;
Ridgedog: I can't stay connected long enough to fix this. Duncan I need help. Antimatter explosives as fast as you please. This will eat the world.
When the thing first went off, Sips was almost on top of it, and was killed instantly. Sjin, on the other hand, was in the tunnel a certain distance away, and got caught first on the edge of the floor, then on a wall he built, as he was dragged in. Since he couldn't escape the gravity, he was stuck, completely helpless, for a long while with his only protection slowly being eaten before it finally caught up with him.
Another thing that was rather freaky was how, after the explosion, a number of odd things began to happen. In addition to the obvious issue of the wormhole, its pull was so strong that Sjin and Sips both randomly died a few times just walking around outside of their base due to getting pulled into the ground. There was also a point where for some strange reason, Sjin became invisible.
Remember what Ridgedog said shortly after Duncan's anti-matter bomb blew up the underground? 'Ok it's in unloaded chunks. We're safe for now'. That means that any time they go to a new chunk, they run the risk of re-loading the red matter explosion.
The explosion itself is horrific, as it can consume the entire world and at first Simon, Lewis, and Duncan were oblivious to it and assumed it was something less lethal.
Sips_: There may or may not be a giant wormhole under our base that keeps killing us.
The sheer amount of devastation after all was said and done. It was a hole that went down to the bedrock that was about the relative size of a couple of city blocks!
As revealed in a later video, Duncan missed some spots with the rejuvenation missiles.
It was so bad, Simon decided to create a treaty banning all Red Matter and Dark Matter bombs. Keep in mind this is the man who ordinarily loves Stuff Blowing Up solutions...
Proving that Sips and Sjin A) learned nothing from the experience and B) are both insane, they set off after the wormhole immediately after the treaty was signed. When they couldn't follow it further due to an ocean, they set up a base and have begun working towards building another Red Matter explosive.
Luckily, they've stopped.
The second missile Ridge fires in episode 24 of Voltz not only sends Duncan (who was directly hit by it) to the End, but also fills the entire base with Endermen.
Horror of the normal and fridge variety inside Ridge's base as well The trophy gallery of Yognaut's heads, and the cages full of animals for experiments are bad enough. And then Lewis also refers to it as the Yoglabs "Black site" stating that it's completely amoral and evil, and he thinks his memories of it were erased so he wouldn't stop them. Considering how close to the Moral Event Horizon Lewis seems to have come in his Yoglabs persona, it says a lot that this place is far worse...
The entire second half of video 25 for Voltz feels like a segment from Fallout, with Simon, Lewis and Duncan climbing through Ridge's heavily irradiated (from the Nuke they used to crack the base open)facility. In between dodging sentry guns and looking for salvage, the group find evidence of horrific experiments that Ridge has been undertaking...
Lewis seems to have turned evil in their Yoglabs series, and offhandedly mentions doing horrible things like chopping up dragons for food and shooting Testificate_MD since the doctor wouldn't let him renew his combat license. Then there's Dr. Srivaramen, who's covered in blood the entire time and has a giant pet mutant zombie named Bort, who he treats like a dog as he asks if it wants any Testificate children to eat.
In earlier Yoglabs episodes, Lewis was often in Suspiciously Specific Denial, claiming that they 'aren't evil or anything', until the Fuerellos' Guns Mod, where he makes Simon join him as he massacres several government agents within Yoglabs who had shut it down, then fully admits that Yoglabs is evil. And he does it in such a nonchalant way it's creepy.
The basilisk attack in "Girlfriend Island". They just suddenly turn up and start killing everything, yet Lewis and Simon have captured them and are bringing them back to the main lab for cloning.
In Episode 38 of Moonquest, they turn up in a land called Sludgepit 2... which turns out to be a nice, snowy world... with meteors and flowers that randomly make them catch on fire. Earlier, a mutant skeleton goes on a rampage and kills Simon with pretty much no warning.
On one of the Christmas livestreams, Kim, Duncan and Simon are messing around in the old Tekkit world. Simon is going through the eggs added by the various mods. Simon spawns a naga. It starts destroying the area. Simon spawns some more. And some more. Bad things happen. Duncan tries setting off a nuke, and it still doesn't kill them. Simon basically unleashed a plague upon the world.
And as of the Apprentice episode 10, the Naga Plague has reached Duncan's castle, and got inside one of his towers, and he still has no idea how to stop them
Kim's Flux accident in the Apprentice is a downplayed example. All she did was fall into the nuclear sphere by accident, and now something is causing her to act increasingly strangely, she keeps going into an odd trance and talking about how pretty the Vi Z node is (at this point it's a swirling vortex of purple and black that even Duncan called terrifying). And what's more, the purple taint on her arms is also in one of her eyes, and is still growing.
Yog Labs has Soul Absorbers and Clone Lab. Two Yoglab employees betray Lewis and Simon and plan to make death permanent. Simon is killed, permanently, but is able to be replaced by a clone—at the cost of his own memories. All Simon from now on are clones of the selfless clone.
The very end of that episode as well, starting from Simon's "Hang on...is that a ro—?". It then zooms in on the robot in question, which has the sign "Nothing Lives Forever" on it. As if we weren't worried enough for Simon before... (and worried about how evil Lewis has been acting)
'Lalnibal Hector' deserves a mention as well. A bad clone of Lalna, who's killed more testificates than Simon, and is now locked up in Yoglabs. According to Lewis, he escaped once. If this is a bad clone of someone who already likes exploding things with nukes, who knows how evil Lalnibal Hector really can be?
Unless you go for the fan-theory that there's nothing wrong with "Lalnable Hector" at all, and that Lewis is keeping him imprisoned in order to (ab)use Duncan's inherent creativity. Afterall, we only have Lewis' word that he's evil, and Lewis is hardly a paragon of virtue himself.
In the aptly-named Midas Touch episode, Lewis and Simon have been using replacers, which replaces any block of material with another material. Out of curiosity, Simon replaces the floor with bacteria.... which spreads and devours the world before being stopped.
The destruction of the Jaffa Factory in Jaffa Quest 105 can be seen as this in-universe, considering they didn't know the ship still had fuel and not even Duncan knew the amount of devastation that could be caused.
In-universe, both Simon and Duncan were stranded on the moon for part of Moon Quest, with only their comrades' voices for company. In Duncan's case, rescuing him was second priority to a laser sentry.
In theseepisodes of YogLabs, Lewis is about to remove the hard drive containing the data for the YogDonalds Simon is in(long story). Simon glances upwards and sees Israphel himself glaring down at him right before the hard drive is removed. When Simon's screen returns to normal, Israphel is gone.
Two more from YogLabs: One: Lewis completely controls Simon's brain functions. We see multiple times that he has a control panel that simply hacks Simon's brain which he has demonstrated can mentally change Simon's age backwards, at least. We also see and hear of him programming in false memories and giving multiple Simon clones the same exact belief that they are the real Simon. Now, while we know Lewis is Simon's friend and he wouldn't use this technology for irresponsible purposes. However, if Lewis is as close to the MEH as we think and Simon is not on board with it, as wee see evidence of, Simon might stand up to Lewis, then have Lewis simply tell him to stop breathing. And also, every clone that dies is gone. They're all the same hilarious, fun-loving, hole-digging, Jaffa-munching guy we know and love. And there is no shortage of ways they've died. Oh yes, and in relation to the above post, Israphel isn't wearing his usual dark robe/cloak. He's wearing Lewis' clothing.
Lewis is eerily calm about the fact that he can trap Simon within a hard drive.
Their goal in Hole Diggers is to follow Simon's Dwarven instinct and dig deeply and greedily and wind up in a dimension called the Deep Dark. The Deep Dark is a dimension that starts you off in a small box and if you dig down, empties out into a freakishly massive cavern. As if that wasn't enough, being in unfiltered darkness slowly kills you. Simon's unaware of this fact until he dies and the world message reads "Honeydew was consumed by the darkness", which elicited a Big "OMG!" from Simon and Duncan. Just to make it even better, there are randomly spawning holes in the world that go right into the void, thankfully Simon has a jetpack.