The Codex Seraphinianus is a surreal illustrated tome which has been shrouded in mystery since its first publication in 1981.
Written by Luigi Serafini, the Codex is full of finely illustrated and totally bizarre scenes showing skeletons getting fitted for new skin, a mother and child wearing strange fish costumes, a horse-insect hybrid, fantastic machines, scenes of people using psychic powers, and much more.
Luigi even made up his own language to accompany these illustrations, and the language has yet to be fully understood. The author claims that the script has absolutely no meaning despite code breaker and linguist James M. Duyer's assertion that he has almost completely decyphered the strange language/code.
To add even more WTF factor to the Codex Seraphinianus story- Luigi claims to have been told what to draw and write by a psychic cat that accompanied him as he put the book together in Rome during the 1970s.
You can read more about the Codex Seraphinianus at Dangerous Minds.