Lol, good idea not to use a pic with an 8 ball in it, bluedemon25!
That made me think of this dangerous toy that my friend Claudia had-we were somewhere between 3rd and 5th grade, so 60s. I was jealous until she whacked her elbow with one of the balls when she had a pretty good click-clacking run going. She cried a lot and loudly. There was no blood, though. Then, I was happy to learn without personally experiencing the fact that maybe it was a good thing I had tiny Superballs instead. Click Clacks were solid, hard and left bruises! Claudia's were purple. Very appropriate warning color.
I can't remember if I got my small Superballs from one of those vending machines like gum ball machines that dispensed them in capsules for a quarter or if they came in a package. I used to roll them against the fireplace bricks and ricochet them to the cat (My dad named him Stupid Cat because he played with the dog and thought he was a dog.) and the cat would bang the ball back against the bricks. It would continue for awhile until Stupid Cat knocked the ball under a piece of furniture. There was a time you could find random Superballs on the playground or out in the street.
I remember Super Balls. I had forgotten until you mentioned it. I believe I had then from a vending machine too. However I vaguely recall there was one I/we? made from scratch which was really cool and it had layered colors. Only a vague memory so I csnt recall if it was a science class experiment or something I did on my own with like a build your own kit or what. They were fun. I remember trying to see if thrown down to the ground as hard as possible how high they'd go.