I was a pretty good pitcher in high school. I'm a big guy, was about 6'4" 215 back then, this would have been about Grade 10, and I had a nasty fastball, I could just blow it by most guys.

My grandma (Dad's mom) was a huge baseball fan for decades and she loved the fact that I was a ball player just like my Dad was when he was my age. She came to all of my games, kept an official scoresheet, was my #1 supporter.

So at a family BBQ one time, my dad thought "After all these years of watching baseball, it would be really cool for her to see what a fastball looks like from the batter's perspective.", and we all agreed that would be a pretty cool experience for my beloved my grandma to stand in the batters box and see what it's like.

So my dad got his catcher's mitt I warmed up a bit, got the arm loose, was feeling good, and my grandma stepped in.

The first clue that this was a bad idea should have been that the first pitch was about 2 feet outside and bounced before it crossed the plate. That was... odd, clearly having grandma there was messing with my head a bit. So I concentrated hard, and the next one I took a lot off, it was almost a changeup but it was right down the pipe. Ok, maybe that first one was just a fluke, it's not like I was on the mound, I was throwing on some grass in the backyard at about 2/3rds the distance of an actual mound. So I smiled, looked at my grandma and said "Ok, here comes a fastball!" and unleashed an absolute heater from about 35 feet away.

I can remember it like it was yesterday, the fucking thing was like a laser beam right at my grandma's head, it had a bit of a rise to it and she was frozen like a deer in the headlights, she didn't even duck, pranged her about two inches above the temple and flew straight up as she hit the lawn. My heart was in my stomach as my dad knelt beside her and she groaned holding her head and I ran over apologizing.

Ultimately, she was a little woozy but got up after a minute or so and toughed it out, said it wasn't my fault, said she was fine, etc. and she seemed fine afterwards, I was horrified and felt like an absolute fucking asshole for the rest of the night, and my Dad was pissed at me even though this whole thing was his idea.

She ended up developing pretty severe parkinsons and dementia a few years after and even though logically I'm fairly sure that I didn't cause it (I mean, one sub-concussive event? Probably not, right?), I still can't quite shake the feeling that I ruined her brain that day :(