It kept surprising me, too! Which is, I guess, what you were saying about genre. I mean, it wasn't surprising plotwise (e.g., it was pretty clear what the Caddys were pretty early on, and I'm not convinced it wasn't supposed to be obvious, and while I didn't guess the ending, it was mostly because I wasn't thinking about it at all), but, like, even thematically -- at first I thought, oh, it's a book about the particular hell that's middle school, and how it's not actually much more implausible than magic -- which itself would be a sufficient theme to hang a book on -- but then it turned out to be a book about a very San Francisco city romance, and how we change the narratives about ourselves, which would also be a good theme to hang a book on -- but then it was about how differing modes of thought can screw people over, apocalypse style, and maybe it was always about that from the very beginning -- and, just, wow. I mean, you note that lots of books change their spots, but I'm used to generally just one major change in genre (like, from mystery to SF, or something like that), and not also the deep thematic underpinnings also changing, or transforming, or something. Really just -- yeah, like you say. Never read anything quite like it.