Once I bought a big chinese firework, 4 units. Don't remember the title, it said something about "devil" or "inferno". Well... it was rather a bomb.
You put it on a butt end, fire the fuse. It fires the first time, jumping high into the air and then explodes with a lot of noise. I wanted to test one and chose the one in which the fuse was torn off. I fired it and quite rashly threw it from me. UNEXPECTEDLY it blew up in a fraction of second! It flew towards me in centimeters from my head, then it hit a garage door beyond me and UNEXPECTEDLY exploded. I was shocked. (Actually I knew how it works, but it happened too unpredictably). Only when I returned home, I got how dangerous was it.
I was 14 or 15 years old. That new year I fired all the remaining bombs and never more bought such stuff.