If you dislike slasher flicks, probably give this one a pass. That said, this horror/thriller subverts enough expectations to be genuinely disturbing in a way I haven't seen often.

A 12-year-old boy and his babysitter experience a home invasion, and it goes badly wrong in ways you wouldn't expect. (Don't watch the trailer, it's 100% spoiler.) Both are played by age-appropriate actors who give outstanding performances.