I just thought of another evil genius invention. Jr High I walk into the library and an epic spitball fight is underway. Creative genius Kevin And Jim pull out the big guns.
They had taken the typical clear plastic bic pen, removed the inside so its now just a hollow shell and taped up the little hole (remember that hole?).
They then cut a metal hanger up so that its a small ramrod like piece. You put a spitball into the bic tube, force it down towards the end using your ramrod. You then take another spitball and push it into the front tube section and leave it.
Now, when you ram your metal ramrod into the tube, the force and pressure from the first spitball makes the spitball at the end explode out of your bic spitball gun and you will win the war. Amazing how loud and powerful that device was.
I have a design for something similar, except it uses the charge from one of those small confetti poppers to launch the spitball ...