The chumbuddy can hold a full size adult inside of it, just like a great white, and double as a stuffed toy. You can even remove the dorsal fin to use as a pillow, but that'll probably just make him mad.
Check out the detail and intricacy of this Lego Death Star. It's so huge that it has its own gravitational pull. Your kid will love you for getting this, but beware, it can destroy entire planets at will.