And no wonder! For Satan himself transforms himself into an angel of light.
— 2 Corinthians 11:14
When I was a kid, I collected snakes. I am not really sure why, but I used to be fascinated by them. I had all kinds. I would read books about snakes. I would go out looking for them and bring them home. And I was bitten by snakes many times. I discovered that you never really know what a snake is thinking. Snakes aren't expressive creatures; they are cold-blooded reptiles.
Snakes are nothing like dogs. You know where you are with a dog at any given moment. When a dog looks at you with his tongue hanging out and his tail wagging, you know he is a friendly dog. But if the dog shows his teeth and the hair on his back is standing up, then you know he isn't happy. You always know where you stand with a dog.
But you never know with a snake. A snake has the same expression all the time. A snake will suddenly bite you, and you won't even see it coming.
In Genesis we're told that "the serpent was more cunning than any beast of the field which the Lord God had made" (3:1). Notice that he didn't show up and say, "Hi, I'm the Devil. Maybe you have heard of me? I hate God, I hate you, and I want to destroy you. I was wondering if you wanted to hang out. I have some ideas."
The Bible does say that Satan was a serpent, but it doesn't say that he slithered. He slithered after he was cursed (see Genesis 3:14). We don't know what he looked like, but there was something fascinating, interesting, and appealing about him. He was somehow attractive, and sin is always attractive.
The Devil may be wicked, but he isn't stupid. He comes with subtlety.