This is a Texas rat snake, a harmless serpent unless you are a rat. I met him in a grocery store parking lot in a residential area in North Texas. The rat snake is not poisonous. Like most snakes, he wants to be left alone, and he would prefer to crawl away instead of confronting you. But, like any animal (and some humans!), he will bite if you get close enough and threaten him. His bite hurts but will not harm you. Wash the bite with bacterial soap, to prevent infection. Then apologize to the snake.