Candle Cannon??

Have you ever seen those "magic" ball-of-air cannons? You know, the ones that have a rubber diaphragm on the back of a largish conical tube - guaranteed to jam dirt and debris in your eyes at 20+ feet?

Here's a Much Bigger one.

This one was built to help celebrate the 20th anniversary of a sandwich shop, of course. What... you were expecting something relevant?