While some may believe it's all snakes I have a hard time thinking so. For me I have a personal belief that the snake influenced by Satan was IMHO the Reticulated Python. Why? Well, being the longest* and most aggressive snake in the world it just makes since.
Although, being around 6,000 years ago that snake that he influenced could've been extinct by now. As I have read one book on snakes (as they are an obsession), they had in the book about the "fist snake that had evolved," which got me to think that that was the snake influenced by Satan. (Not that I believe snakes evolved)
However, if anyone would like to share their thoughts, you're more than welcome to.
*The Anaconda is the biggest snake while the R. Python is the longest. The Anaconda being more heavily bodied (or bigger in width).