Whats a good camera to use to spy on my brother with?

my brother is a habitual liar and hes always breaking the rules. my mom and i want to buy a camera that could go in his room without him noticing and would be easily accessible to watch the videos on it. he usually has his room pretty dim and his shutters shut, so night vision would be good too. it would be nice if it could be hard to find yet easy to get to. suggestions?