I'm going with K.K. Dirge for sure. Hypno is pretty creepy too though. It instantly makes me think of Aika Village so I picture a little girl with blood splattered on her with an axe.
I remember there was this dream town I visited where I went into their house and it was all pitched black with K.K. Dirge playing in the background. It creeped me out so bad.
I don't find K.K. Oasis creepy at all. I end up dancing to it.
Edit: um so someone in the comments section on youtube pointed this out and it makes K.K. Dirge even worse. A dirge is a song they play during a funeral and before you bury someone. Awesome. I'm not sleeping tonight.
Hypno K.K. for sure. I only have it playing in my basement, which has two creepy dolls and a only a red lava lamp to light the room. If I play it in my main room, I get too creeped out and end up leaving in a hurry.
I like Hypno K.K.... My mind imagines a psychological thriller when it hears it... K.K. Dirge makes me imagine a dark corridor and at the end a dark figure you can't comprehend, you can't go back because behind you is a wall and with each step you take towards the figure, the corridor grows shorter, the wall follows you... and the dark figure grows several limbs and forms which seem not human... but you can't still understand what it is...
K.K. Dirge of course! It makes me think of occult sacrifice :'D one of my favorite villagers Lucky has it playing in his house, and the more i listen to it the creepier it gets, but I actually still quite like it, i bought it hehe~ cx