This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / BrainScratch Commentaries
Nayrman's laugh when he is cracking up is incredibly ominous, specially in the Final Fantasy 6 and Sonic Adventure playthroughs.
In Part 18 of the RAWS for Arkham Asylum, Ryan used one of Joker's themes from the Animated Series as filler Audio that worked well... maybe a little too well for its own good without their commentary... At least untilAdam Westkills the mood.
Ryan: So how are we going to keep this rage up for four more parts?
Johnny: I will find EVERY excuse I can!
Chalk it up to crappy quality or whatever... but this particular image of Ryan from Momocon 2013 is a bit... ...offsetting to be honest.
Possibly nothing could sound scarier than puppet master Waluigi, the thumbnail for part 13 of Mario Party 3, the fact he literally has puppets of Daisy,Yoshi, and Luigi (in manic depressed form no less) doesn't help. Thank you, Johnny!
Ryan gets VERY unsettlingly angry at Johnny for throwing him off of the roller in Part 22 of Super Mario 3D World.
Johnny's angry outburst in part 17 of the Mario Party 3 playthrough after Waluigi wins by going in circles
Johnny: YOU MOTHERFUCKER!!!!! YOU SON OF A BITCH! IT DOESN'T WORK THAT WAY! ANARCHY DOESN'T WIIIIINN!!!
Lewis' continuous battle with the gnome menace! while thought to be a joke, the chance that it could be real is a very scary thought...
In the Five Nights At Freddy's live playthrough, one of the nights has Ryan actually run out of electricity. The game's events itself are plenty frightening (the doors open, the lights go out, the laptop turns off, and Freddy can be heard on the way), but it's even more unsettling to hear the other commenters saying in hushed voices how there's nothing to do but play possum and pray that Ryan can reach morning before Freddy arrives. The atmosphere honestly feels like they're trying to hide from something in real life. It makes the reveal that Ryan only just managed to make it to the morning before dying that much better.