My shop mate does quite a bit of brazing in his bicycle rack business. One element of that process is something called flux. Flux is a chemical that, when heated, first crystallizes then turns to a gas that displaces oxygen (the enemy of any good brazed or welded connection). He likes to use a liquid flux and keeps a small stock of it on a shelf.
Yesterday he noticed that one of his cans has sprung a small leak and this is what happened. With the exception of the waste, the result was pretty cool.