It appears these were sold in the 1950s and 60s.
Photo of real ones.
Youtube video which shows a few shots of them in action, but it's not the exclusive focus of the video.
I'm old enough to have had lawn darts for a little while back in the day. I never injured anyone nor got injured, but only by sheer luck. It didn't take long to figure out the most "fun" was to throw them up as high high up as possible (i.e. straight up) so they would land and stick more in the ground.
.........yeah