Something explosive?

Do you know of a chemical I can put on metal "stage" weapons that will make a crack, pop, spark, or bang upon impact? I'm afraid to google anything about it because I'll probably use a bunch of keywords that are wrong and then get arrested.

I'm doing costumes and props for some weird improv thing for a theater troupe, and it's crunch time.

>>8
You'd be surprised.
One of my high school friends actually made a mini stun gun with those materials.  The trick is that you don't keep the DC current on constantly.  You close the circuit right when you want the spark; with low resistance and inductance, the current on the input end of the transformer will shoot up rather quickly.  The output will then generate a short spark if the ends are close enough.  To prevent the wires from melting, you disconnect the battery, and rinse & repeat.