Just because they are animated, I don't think the Treehouse of Horror episodes count as "kiddy." Blatant homages to works like The Shining and The Monkey's Paw. And some truly horrific/gory stuff (albeit played for laughs). I do think a SZ is more likely, but I think Matt Groening is far more likely than, say, JK Rowling to go along with something like this.