Here we have an individual throwing (and batting around) gasoline-soaked flaming tennis balls.
When I was younger, back in the days when beer and soft drink cans were still made of steel, rather than aluminum, it was possible to cut the tops and bottoms from two or three cans, tape them together to make a tube, and add one more can with several holes in one end and a single hole in the other to act as a combustion chamber. This was known as a “coke can cannon.” Squirt a little lighter fluid into the combustion chamber, shake it around to increase the amount of vapor, drop a tennis ball in the other end, and launch it by holding a match to the hole in the bottom of the combustion chamber.
If you “wet down” the tennis ball with lighter fluid before putting it into the tube, it would come out flaming, which looked cool if done at night.
Of course, you did have to worry about the combustion chamber exploding. I never had that happen, luckily, but I did once put a significant dent in the garage door when recoil caused the cannon to jump from my hand.
As I said, one of the stupid things I did when I was younger.