Within Chuck Palahniuk's 2005 collection Haunted, many fans count The Nightmare Box as their favorite story. The story is about a box people look into, that always shows the same image, yet drives the viewers insane and to commit suicide.
This story (maybe even more so than Guts) also seems to inspire the most creativity from fans, as evidenced by the slew of YouTube shorts online. (here, here and here, to show a few) But now someone has taken this obsession up a notch with this amazing portrait.
The above work was painting by Mike Flinn. Check out his website here. And here are some words about the work, from the man himself: