It's no secret that Itoh Junji is actually a comedy manga author. It may be because his manga are so scary that they loop around and become funny, or because they're just funny. Anyways, back when the Gyo OVA was announced, I lurked komica (the Taiwanese 4chan) to see what they thought about it. Several of them said something to the effect of "where the fuck is my Cat Diary anime?"; another said, "I was so happy for him when he admitted that he was a comedy author by releasing Cat Diary". I agree with them. Itoh should just make comedy manga.
Anyways, this manga ranges wildly from "wtf am I reading" to "holy fuck this is funny". Give it a try.
Itoh Junji's Cat Diary ch 1 (IF)
Itoh Junji's Cat Diary ch 1 (MU)
Itoh Junji's Cat Diary ch 1 (4SH)
Itoh Junji's Cat Diary ch 1 PSD source (IF)
Itoh Junji's Cat Diary ch 1 PSD source (MU)