Kaidan Neko no Mofuku

The hero is a high school student with the very odd name of Yubi Chizuo ('Finger Mapguy'). He lives in a cheap boarding house with a scummy river oozing by in front of it. The locals use the river as a handy place to get rid of their trash. Flies result. In abundance. The infestation gives Yubi Chizuo no end of trouble. One evening, a particularly large specimen buzzes up in front of Chizuo, and addresses him in fluent Japanese. Understandably shocked, our hero swats the six-legged prodigy flat on the spot. Chizuo finds himself haunted by the Ghost of the Talking Fly. And then he realizes that a mysterious black cat has started tailing him everywhere he goes...

(Source: Comipress)