You'd think Nerf guns are safe, for kids especially, but this one mod from Make's Dan Spangler, includes a propane powered dart cannon. It'll kick some ass in a whiteboard. Its that powerful.

The nerf gun was assembled from PVC pipe and is fueled by BernzOmatic propane torch, giving it more kick for the foam dart to put a noticeable dent on a whiteboard. Check it out after the jump!

[YouTube via Make]