"Danger! High Voltage. Do Not Touch. Death or Serious Injury May Occur," reads the yellow sticker on the side of this 1.25 Kilojoule DIY coilgun. Watching this video of it in action, that sounds about right:
I don't know what kind of school this kid goes to, but I doubt my shop teacher would have allowed me to build an electromagnetic coil gun that can send a round through a soda can.
If an atomic zombie is molesting you, get this coil gun, aim with its built-in laser gun sight and pew-pew a metal projectile at 110km/h into his rotting cranium, with a total energy of 18 joules.