"I'm Possessed" can give off a lot of this, what with the demon randomly appearing and Ian's flashback showing flashes of the old couple being either dead or suffering from Zalgo-ish levels of Eye Scream.
The very end of every 'Extras' video often suddenly shows a freaky expression from a cast member, set to a Scare Chord.
Sometimes it's two or three of them.
The entirety of Smosh Found Dead.
"Best Toy Ever" with the Happy Flying Cow toy stealing souls and causing Ian and Anthony to become obssessed with playing with it forever and ever. The Lyrical Dissonance in the song (Happy Cow Happy Cow, steals your will to live, Happy Cow Happy Cow your eternal soul you'll give) is the cherry on top.