Dead serious: I would pay real money to own a Nerf gun that looked like this. The gun, made by DeviantARTist AjlDesign, uses a modified Nerf Maverick to channel the awesome might of a Big Daddy. As you can see in the video above, it's a heck of a little thing.
AJDesign has put up a blog post describing the process of making the gun, and you can check out a bunch of images below. It has a little basket for the Little Sister!