I'm gen Z, grew up in the city, and I know what that is because we used em in the Boy Scouts. It's for pounding fence posts into the ground. The other end is welded shut and you put the post in the ground, put it over top of it, and pick it up and slam it down a buncha times
They also make ideal launchers for fire works:) especially in areas where the local police get pissy despite them being legal, you can go out to the country side, mount it upside down and fire off some rockets and yank it out and move a few county roads over before the sheriff can arrive.