When I was about, maybe six-ish, we had two Scottish Highland Westies, the little white fluffy dogs and a Yorkshire Terrirer, an even smaller fluffy little shit.
Now one of the Westies was in heat, although she was quite old by this point, and we had her in the bathroom at this point to keep her away from the Terrier, but as I tried to get into the bathroom the Terrier ran past me and he and the Westie started fighting. Me being a six year old didn't understand that even though these were tiny dogs, they were still quite dangerous to my also tiny self, so while trying to grab them and pull them apart I got bit by the Westie, I knew she never meant it because her eyes were closed when she bit me, but she got my thumb and bit down as hard as she could and backed herself up into a corner, pulling my thumb with her, except just my thumb went with her for the most part.
As soon as she opened her eyes and saw what she'd done both dogs stopped fighting and went and hid in the corner, I'm guessing they understood that they just fucked up, with my thumb hanging off, only attached to me by a few small bits of skin and tendon, I rushed out to my brother and went the hospital. I never went to the therapy to regain the full use of my thumb and it still looks really messed up, it's also shorter than my other thumb now and slightly bent in a weird angle, it also started growing two nails on top of each other on my thumb but they're hard enough together that I can actually sharpen them and use my thumb as a really effective knife for about a week before it needs sharpening again.