A Japanese manga artist best known for his "Ge Ge Ge no Kitaro" comics, many of which can be downloaded from this site.
Kley was a German caricaturist, editorial cartoonist and painter. Much of his imagery focused on fantastic scenes depicting humorous and often disturbing imagery, some of which I've posted below. I found the picture above of the giant catterpillar attacking a woman especially creepy.
"Daniel Johnston is a prolific American singer, songwriter and artist. Johnston suffers from bipolar disorder and often writes surreal songs about his hallucinations and mood swings." Quote taken from wikipedia.
