Mister Prism

Looking at the time, you realize that it's past midnight. You need to wake up early for work tomorrow. You sigh and get ready for bed. As you're brushing your teeth, you suddenly remember the nursery rhyme from your childhood about Mister Prism and you chuckle to yourself. Once in bed, you turn out the light and pull the blanket up over your chest. As soon as you close your eyes, you hear a strange voice speak to you from above your headboard. It's a little late, don't you think?