ANIMORPHS. Hello favorite book series ever. But yeah, super dark for a kid. There's that one book down the line where Tobias is tortured for a good half of it and the whole thing with Marco's mum. I reread the entire series a few years ago because it takes about half an hour to read one and it was glorious. I kind of wish there was a series like this actually geared to older kids because there's sooo much that couldn't quite happen in a JFIC.