His Crooked Man series is probably the highest source of nightmare fuel available from Pewds. The thumbnail of episode 1 has Pewds Kubrick staring at the viewer. Not too scary, right? But then in the thumbnails for the videos to come, his skin turns paler and his neck gets more and more elongatedas his eyes turn to black and his head topples over. It's just as horrific as it sounds, plus there's the page image. (You're welcome for that.) Actually justified because the Crooked Man is able to tilt his head to unnatural extents.
The Viscera Clean Up game, as seen in this video. Pewds manhandles a bunch of elves(' corpses?), throws some into a fireplace, and a bunch of other crazy stuff. He frequently says that the game is creeping him out, especially as he's holding an elf head that's staring right at him. And the blood. Oh my god, all the blood.