What could it be?

Got this Large package from Amazon.com yesterday. It's addressed to "Master Sam Covington". As you can see, Sam already enjoys just sitting on the big box. He doesn't have any real clue that it's for him. Although, he now knows when I ask him,"How old are you going to be?" He says, "two!" So cute. I'm a little anxious what could be in there. Mum called on Sunday and told us to expect a package for little S's b-day. She chuckled slyly and said something about us not being "too happy" with it...hmm...