Goodnight... Mouse?

Jack's current favorite book is Goodnight Moon, which he loves so much he took it into the bathtub last week.  Sam was in New York City for work this week, so he went to FAO Schwarz and bought a new copy. I'll let you figure out what Jack's favorite part is... you can't hear it but we got buzzed mid-video by a low-flying helicopter - when Sam said "Whoa!".