VIDEO: Former NASA engineer builds world's largest NERF gun

Now this is an arms race! Former NASA engineer, Mark Rober, explained that some of his co-workers have NERF gun wars and he decided that he was going to have the last laugh.

He teamed up with Ryan and David of Eclectical Engineering to build the world's largest functional NERF gun. This beast of a toy weapon fires custom-made projectiles - made from pool noodles and plungers, at around 40mph and they're capable of travelling a good distance.

The trio break down how the mammoth NERF gun works too, so if you feel up for the challenge, you ca build your own.