Tomie: Complete Deluxe Edition by Junji Ito.
My rating: 5 of 5 stars.
If someone hadn’t read any manga before, and you really wanted to fuck with them, you’d probably show them some Junji Ito. I mean if you wanted to warp them irreparably you’d throw them a bit of Suehiro Maruo – that’s a Wikipedia link, but I’d be leery of actually Googling the dude if you were at work – but if you just wanted to weird them out, it’d be Ito all the way. Because this is pretty much the initial reaction to his work:

I had somewhat similar thoughts.