Your Wrist Rocket story reminded me of an experience indoors.
I was a kid--7 or 8 or 9 maybe. Two of my older sisters were on one of our beds--we had more beds than chairs in our house--with their backs up against the headboard. One was reading the paper and eating an apple. The other was similarly engaged. I was sitting on the lower end of the bed fooling with my beany/ie flip. (A beany/ie flip predates the Wrist Rocket and was oftentimes incorrectly called a slingshot and oftentimes called another name left over from a more racially insensitive time in our history. To make a beany/ie flip, one found a nice fork in a limb, cut it out, whittled off the bark, carved a grove around the two top ends, affixed two strips of stretchy rubber cut from an innertube, and made a pocket for a rock/marble, steely/ie ball from an old shoe tongue. A weapon fit for the king of your block. Such constructions would be impossible now: everyone knows that a kid with the necessary pocket knfie is bound to hurt himself or someone else.) Seeing a carton character on the back of the paper that my sister was reading, I, without thinking it through, let fly with my flip. The rock penetrated the picture, broke the lens of my sister's glasses, and impacted her eye.
At that moment, she was the unluckiest....
There was no serious and/or lasting injury--except to my sensibilities: I, scared and worried about my sister, started to cry and laid face down across a kitchen chair which happened to be in the bedroom. My widowed mother walked past--I'm sure that she was probably more concerned with how she was going to pay for my sister a new set of glasses than anything else--and slapped me once across the butt with a belt. That was one of only three or four times that I remember her ever hitting me--not to say that I didn't need hitting more than that. There was that time that she used the flat side of a butcher knife. I stayed awy from her in the kitchen after that.
BTW, I've known two men in my life that, as grown men, hunted with such a beany/ie flip, and both were deadly. One, when he took his big, long-legged Coyote and Jack Rabbit dogs out, always carried one in his hip pocket. If he saw a squirrel or a cottontail, it was supper.