Looking for a kids book from around 2005 about a kid who goes to live with their grandma and her mannequins

I don't remember much about the book except a few key elements. The main character goes to live with their grandma but there's like creepy mannequins in the yard. The book goes to great lengths to describe how creepy and life like these appear but they never move.

The end of the book someone breaks into the house or something and it's heavily implied the mannequins actually came to life and saved the protag and their grandma, but not explicitly said