The other day I was startled by an unexpected visitor in the yard. It was a snapping turtle. Sometimes in the spring they crawl forth from their usual haunts, those being the mud at the bottom of ponds and creeks, and travel about by night, in search of who knows what - better hunting grounds perhaps, or mates. It spent the day in the shade of the ancient oak tree by our house, then moved on.
This one is fairly big, but I've seen much larger ones. I remember one such, dredged up when we enlarged our pond, bigger than a washtub, that splintered a broomstick handle in half with a single snap. Gladiator Gladys got that one, and, presumably, ate him. I thought they all were marvelously monstrous, and made terrariums to keep the baby ones in.
The story is that if one gets ahold of your toe, it won't let loose until it thunders, which, luckily, is quite frequent this time of year.
I wouldn't advise testing for myth. Considering what I've seen it would be the toe that comes loose first. But the image did keep its grip on my imagination, and now I consider these turtles symbols of persistence, and because of that reminder, just when I needed it, welcome.