Author Existence Failure: Hergé died partway through his work on Tintin and Alph-Art; the unfinished draft has been published as part of the regular series of Tintin albums.
Creator Breakdown: Hergé wrote Tintin Tintin In Tibet largely as a sort of therapy, to resolve the emotional issues he had following his divorce and the distressing dreams he'd been having that involved vast white landscapes. It is widely considered to be his masterpiece. However, it caused Hergé to undergo another Creator Breakdown — after the book was released, he decided that there was no way he would ever write such a good Tintin story again, and effectively gave up trying to do so. The remaining three Tintin stories were released at a far slower rate than the previous ones, and took the form of experimental character pieces which tended to mock the characters Hergé had been writing over the previous decades. Tintin and Alph-Art might have seen a return to the more traditional storyline, but we'll never know since Hergé sadly suffered Author Existence Failure with the story only half-finished.