It looks like these Swedish guys figured out a new way to have fun with fireworks by using them to break up a frozen lake. They start off by tossing in a glorified firecracker before graduating to something with a little more firepower when they grab a large bottle rocket.
After lighting it and letting it rip, the bottle rocket causes a pretty impressive underwater shockwave that manages to crack the ice in a fairly large radius. Hopefully, they at least went back and picked up their trash.
We wouldn’t recommend trying this at home, but they may have found the next version of fishing with dynamite.