Esp. with the holidays right around the corner...just a friendly warning that toys with magnet/metal sensors and toys that are about to run out of battery will randomly make noise on their own, especially if there's a thunderstorm! You may think the toy is possessed, but it's normal
My ds left one of the Melissa and Doug puzzles with sound half done in his playroom, and when I went in to shut the light off, the fire engine sound went off and made me jump out of my skin even though that's happened a hundred times before!