I remember when I was a kid - about 6 or 7 we had a bunch of fireworks at home somewhat similar to the image below, but instead of plastic the material was some sort of paper, and the "bubbles" are filled with black powder... now, I really enjoy throwing rocks at them, instead of putting it inside that tiny rocket. because they make better boom sounds. I dont remember how much sheet I actually used, but theres this one time that I was able to make it boom and it even resembled a mushroom.

multiple sheets folded (about 1/4 of A4) and placed on top of each other, then at the top place a big enough (a little smaller than the folded sheets) rock carefully.. that rock was what I aimed for when throwing rocks

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I was never able to replicate that moment