This morning, I walked out front of my house to find a medium-sized snake balled up on my driveway beneath my motorcycle. I spotted it from my porch so I didn't walk any closer. I believe it was a Texas rat snake.
I've seen a few snakes in my area but none really up close, so I watched it curiously for a few minutes. It seemed to be acting oddly - its head was tightly bent sideways at its "neck," and it was slowly coiling and writhing while opening and closing its mouth. It didn't seem very alert.
Then, a friendly neighborhood cat began batting at the snake's head, and while the snake was not acting aggressively, it did haphazardly snap back in self-defense a couple of times.
I (subjectively) assumed that the snake was injured or otherwise "done for," so I ended up moving it into the street with a long pole and crushing its head with a large rock. I had taken its lack of objection to agitation with the pole as another sign of distress.
I really don't like killing other creatures. In retrospect, maybe I could have handled the situation differently, maybe by capturing the snake and releasing it somewhere else. At the time, for whatever reason it seemed like it was suffering and I felt like I was doing it a favor, as well as potentially saving some local pets from injury.
Moral questions aside, does it sound like this snake was in fact behaving abnormally? Are the actions I described typical of a distressed snake (at least of this species), are there other plausible explanations, or is it unclear? I can elaborate if there are any specific questions.