We have this puzzle from Melissa & Doug
It is a puzzle that makes sounds - i.e. the fish makes bubbles, the cat meows- you get the picture. It is in Micah's toy pile in our lower level. Each night the last person to come upstairs has to turn off all the lights. Invariably, when we turn out the lights, one of the sounds from the puzzle would come to life - usually the bubbles, which can actually sound very scary when you aren't expecting it. I think I almost cried the first time it happened - surely there must be a ghost in the basement who sounds like bubbles, right? I finally realized it was the puzzle - and that this ghost just must like to play with the puzzle the minute we turned out the lights. So, I would turn them off and bolt up the stairs two at a time followed by, "MEOW... MEOW."
I FINALLY figured it out - because I am so smart - it is the LIGHTS! This puzzle makes the sounds when the piece is returned to the puzzle - the chip underneath recognizes that it goes dark when the piece is placed in the right spot and makes the noise. So, it turns out we do not have a puzzle-playing ghost, or basement monsters who like kittens. Thank goodness.
P.S. I am only telling you this because you may have this puzzle too and you are currently being terrorized by it as we were. It's a public service announcement, if you will.