There was a book I read in middle school. It wasn't spectacular, but I can't seem to get it out of my head.
In it, there were siblings -- maybe three -- who got kidnapped by aliens and brought to this place where they, and many other children, had to perform death-defying stunts constantly. All the other children were orphans and these siblings were kidnapped because the captors thought they were orphans as well, but were wrong.
The youngest sibling is a little girl with a rabbit doll and this doll predicted who was going to die next. The little girl actually used it as a puppet and spoke in a strange rhyme like "hip hort hoi you all goan die" or something along those lines. The rabbit also had a strange accent when speaking, like it was prone to ebonics or somesuch.
I remember the eldest brother got worried that his sister was going crazy and tried to get her to stop predicting things, but I'm pretty sure she said she couldn't control the doll.
There was a lot of dialect in the book. I remember because I've always been a stickler for grammar, and I used to correct the children's grammar as I went along.
I remember the twist at the end was that this was all some science experiment to keep rich old people from dying. The elderly wore these strange alien-like costumes so they could absorb the fear from the children. And these children performed these stunts because the fear they felt made the old people younger somehow. The main characters get released from this place when an old woman hears that they've been wrongfully captured. I think a total of three or more children die in this book.
Really bizarre. I remember that I didn't like the book very much. But it has stuck with me. I would REALLY appreciate any help finding it.