Oh! I don’t remember the name Ker Banger. But clacker ball rings a bell. Maybe mine were generic.This link will tell you how dangerous this toy is & the name also!
https://www.cpsc.gov/manufacturer/chuck-howard-toy
Mine never shattered but if you got the rhythm wrong they could hit you on the hands or arm, and you needed to keep your arm extended or they could hit you in the face.
They were fun and the sound of them hitting when you were doing it right was very satisfying!
Strangely I have a sort of muscle memory about how to do it. Start low and build up momentum until the balls had enough speed to swing vertically up and hit both top and bottom. Bet I could still do it if I found mine in the attic!