and how did acm city get on fire!?!?!?!?!?!
it's called an emitter. you use the wrench to call upon the mighty power of the Engineer by pressing Q, and he will give you his toolbox of power,containing a wrench, hammer, and printing gun. and when a brick is struck with the wrench, the Engineer knows to command the brick to burst into flames.(this is where the mighty Pyro comes in)