Bacterial Contamination is personally one of my favorite Vocaloid songs, I adore the smooth and grotesque animation and Miku's deeper voice which I believe is Zatsune Miku, though I could be wrong. I highly recommend it, but then I don't find such things too disturbing. (If you really want to be disturbed, listen to
Akaito's version of the song. O_O... Hot.)
I love Kikuo's songs, known for having creepy meanings and I recommend his songs
Breaking Things into Pieces,
We Should Not Do Bad Things and the one with the creepiest, saddest and most disturbing meaning-
Don't Look At Me in That Way. Though
I'm Sorry, I'm Sorry is a very close competitor.
Not sure if you're still looking for songs, but I suggest those. Some special mentions are
Okaasan,
Kagome Kagome,
Story About a Poor Rabbit,
50/50,
Rotten Girl Grotesque Romance and
Fear Garden (very nice hands in that one hehehe~)
Creep on, my comrades.
-I now see the original question was just asking in our opinions, but I was responding to the previous page I saw when I clicked the thread and read people mentioning what they'd seen and hadn't. So far none have kept me up at night, but then I like dark tones and the adrenaline rush that comes with fear. Bacterial Contamination is still the best to me.
I also suggest some bonuses to all Len lovers out there-
Psychotic Len's Love and
True Love Restraint which feature yandere Len. Other than that, I think only a certain PV for
Cantarella is a little creepy because Miku is shown so young and Kaito's a little uh... aggressive. To relax though, I recommend the more lovely Cantarella video
here and
Gakupo's Whisper version of it which is especially soothing and brought to you by Satan/Lucifer~ The end-