I foolishly ran over a rattler on purpose, while coasting down a steep mountain rode on my old Columbia when I was a twelve year old brat. Darn thing flipped up when the front wheel hit it, and got caught in the rear spokes for a couple of revolutions. Blood and guts everywhere, and me trying to ride with my feet on the handle bars, while waiting for the bite I knew was coming. Thankfully, it didn't bite, and didn't stop the wheel, but I'll never do that again!